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Brief Summary of Minutes

Monday, January 29, 2007

NCR-46

Welcome and opening remarks
" -Wade French welcomes one and all to the meeting
" -Minutes of 2006 meeting are accepted
" -No nominations for executive at this time
" -Discussion of separating NCCC46 and NC-205
" Billy Fuller offers Sioux Falls as location for 2007 meeting, Lawrence Bledsoe proposes St Louis  no decisions at this time

Old business
" Management guide funds are available from NCIPM Enhancement grant awarded to Joe Spencer
" Ken Ostlie: Economics and Management chapters of the guide must be revised before moving forward with publication
" Drafts will be given to all by Feb 1, comment requested by Feb 23. Target for completed document to Julie Todd by late March
" Christian Nansen discusses option of placing interactive modules into website where final management guide will be housed, but who will manage updates and add new content
" Ostlie stresses that there will be links back to each state resource, make the document readily updatable at any time
" Billy mentions that an insecticide section is essential, the issue is how to update and keep current
" Shields proposes to link to state-specific sites for appropriate geography-specific issues (i.e. silage vs. grain, silk clipping in sweet corn etc.)
" Spencer states that $9,254 is available in the IPM-enhancement grant, waiting for the completion of the draft
" Porter mentions that using Apollo for pdf, instead of Acrobat, would give options for video imbedding and improve updatability
" Hibbard, Spencer, French stress that at this point, getting the design figured out is secondary  moving on to getting the guide published is key
" Shields proposes formation of a committee to discuss and oversee web development

Distribution, Abundance and Species Composition
" Turner mentions heavy drought in South Dakota made 2006 a heavy RW year overall
" Hibbard  typical RW year
" Boetel  more NCRW that WCRW in ND, this is mostly qualitative data
" Shields  NY state largest problem was flooding/drowning of roots
" Hammond  OH, very high larval pops, western variant continues to expand range in the state based on soybean yellow sticky trapping
" OH, diapausing NCRW not found as expected
" Smith  Ontario: high larval pops, predominantly WCRW, predicts more next year, corn-on-corn acres are increasing
" Bledsoe  IN, early May cold spell killed many seedlings, unusual early season conditions, uneven emergence, overall an average WCRW year, NCRW continue to be rare
" Krupke  IN, ELISA analysis of RW gut contents indicate that this analysis is a good predictor of variant range
" Spencer  IL, WCR variant into wheat, soybean, etc., as measured by movement indicates low incidence of beetles in wheat  though other IL data shows high damage in wheat after corn
" Spencer  IL, high WCRW populations south of I70 for the first time, rotation-resistant continue to move west, NCRW relatively rare
" Sappington  IA, WCR variant still spreading west as measured by emergence traps, NCRW are becoming more prevalent statewide from year-to-year
" Wilde  KS, No formal study of RW populations, based on insecticide trials an average year
" Ostlie  MN, extended diapause NCRW common throughout state, no reports of WCRW in first-year corn this year
" Meinke  NE, long-term drought in west, high WCRW numbers and damage in west, more NCRW in east, no WCRW variant documented yet
" NCRW are main source of problems in first-year corn
" Cullen  WI, drought in NW part of state, high damage in this area. Reports of NCRW extended diapause increasing in some areas (lower 2/3 of state, Eau Claire area)
" Porter proposes that efficacy data is included in the record of the meeting within its own section (in each state report), not in Management section as it currently appears
" Motion is passed

Behavior and Ecology
" Sappington: Oviposition in non-corn habitats  collected soybean adults vs. corn adults, used microsatellite markers to search for differentiation
" No structuring detected, no barriers to gene flow
" Using 250 AFLP markers, compared known variant vs. non-variant
" 1 marker was weakly linked, and is not diagnostic (i.e. present in both types)
" Spencer: monitoring WCRW variant using QuickStix looking for soybean herbivory
" Problem: using RR trait to detect, this is becoming less and less soybean-specific
" No differences between # of beetles testing + for consuming soybean within soybean fields BUT significant differences when same test is run on first row of corn (order of magnitude difference)
" Using Cry3Bb1 to document movement in Bt/refuge fields. Movement rates of 15-17 m/day, averaging to 16 m overall throughout season
" Most females mating in refuge are teneral, but in transgenic more are completely sclerotized
" Shields  NY: aerial sampling of insects, 1000 cu.ft of air sampled/minute using plane, can be applied to WCRW movement, possibly in 2008?
" Krupke  movement measured by Pherocon AM traps indicates that emergence early in season peaks in refuge area, also more beetles trapped in interior vs. edge.
" Corn or soybean adjacent favors more adult WCRW captured (vs. pasture, wheat etc.)
" Preliminary results of movement experiments indicate male movement to calling females is highest within strip refuges, lowest when refuge is adjacent

Lunch

Frank Gilstrap: 2006 president of the ESA welcomed the group, spoke about TAMU research center

Behavior and Ecology (contd)
Mating behavior
" French - Larger males in NCRW mate more than smaller males
" Females mate maximally 3X (aedeagus inserted) in Petri dish, measure fecundity and oviposition on Petri dish substrate
" Large male vs. small male vs. average-sized male, documenting antagonistic behaviors

Mike Schwarz (Bayer)
Corn Soil Insecticides: Future prospects
" 79 million acres grown in 2006
" key questions: Will pyrethroid-based insecticide efficacy decrease due to spraying of variant adults? What are treatments of choice for refuge acres?
" 23 million acres treated with soil insecticides in 2002, 11 million in 2006
" Foliar-applied rates have declined at similar rates
" Requests a dialogue with academia to preserve old, yet effective, tools (Aztec) for use in treating refuges
" A primary issue is compliance with IRM refuge standard  no documented numbers, but very low compliance

Rearing: Resistant colony w. transgenic corn
" Bruce Hibbard  8 generations exposure to transgenic corn, greenhouse rearing study  non-diapausing strain
" Field-test of generation 6, survival on transgenic corn survived 12-fold more than unexposed colony (larval recovery only, no adult recovery)
" No increase in tolerance of 3 generations selection vs. 6 generations selection
" Lisa Miehle  resistant males + susceptible female and vice versa. Larval recovery of progeny indicates intermediate levels of resistance.
" Similar study with removal from selection colony indicates that resistance remains even 3 generations after rearing on isoline only
" Mechanisms unclear at this time

Rearing: WCR non-diapausing colony
" Wade French  currently rearing 17 colonies in SD, ranging from insecticide resistance, rotation resistance, wild-type etc.
" B.t. resistant research colonies underway as of 2006
" Discussion of the ease with which resistant colonies can be selected for in the lab, Shields mentioned that this data should be out in the open to increase awareness of the risks of resistance
" Spencer motion: to identify a committee to prepare a simple statement to EPA stating that refuge compliance is not adequate and that WCRW exhibit high levels of resistance in greenhouse studies
" Meinke adds that ethanol production will hasten the development of this resistance
" Motion to elect proposal-writing committee passes. Meinke, Spencer, Onstad, Shields

Extended diapause
" French  examining patterns of inheritance for diapause trait, mapping genes responsible for trait using microsatellite markers
" Meinke  verified extended diapause in NE
" Similar frequency of extended diapause to MN historical levels

Other Diabrotica extended diapause
" Meinke - Biological relationships of D. barberi and D. longicornis (non-pest, but can survive in corn)
" Longicornis exhibits extended diapause, is it heritable/moving into barberi
" Fitness of hybrids - early results suggests that the hybrids are viable (barberi males, longicornis females)
" Beginning mating preference studies, field and laboratory

Alternate hosts
" Hibbard  crabgrass and giant foxtail interaction w/ Cry3Bb1 corn: in the field no effect of weedy fields, unless forced to move off weedy hosts (by spray with glyphosate), to be published in J. Econ. Entomol later in 2007
Genetics of Diabrotica
" Sappington  genetic variation in colony (non-diapause vs. diapausing, variant vs. non etc. etc.) vs. field-collected wild-type
" Found loss of variation in non-diapause line after 190+ generations in lab
" Diapausing colony no different from wild type
" Work with Ratcliffe at UIUC developed EST microsatellite library from WCRW heads, these are expressed in the phenotype, therefore not suitable for population studies
" Found 17 microsatellites that are suitable for population studies because they are conserved
" Submitted to J Heredity for 2007 publication
" Meinke/Siegfried  found marker for diagnosis of cyclodiene resistance
" Also searching for novel target sites for insecticides in RW gut
Tuesday, January 30 2007

Management
" French  ethanol production skyrocketing in 2006, more in 2007.
" Discussion of the effects of acreage shifts on prevalence of the variant

Future of IPM/IRM
" Ostlie  discussion of the fact that if refuge is treated, then the entire area must be treated with foliar insecticide
" Spraying for SBA  are significant numbers of WCRW killed during these treatments? Shift toward more preventative treatments, vs. reacting to actual infestations
" How to scout fields to make treatment decisions in Bt/refuge areas? Are refuges scouted more intensely.
" Most scouting methods and thresholds are obsolete, what do we focus on for future IPM systems? Suggestions: refuge deployment strategies, insect movement, sustainability of continuous corn systems
" Shields discussion of nematodes in inoculative biocontrol. Heterorhabditis is effective against Diabrotica, but often not effective in clay soils

Modeling of resistance
" Onstad  Mentions Mitchell has modeled NCRW resistance development under extended diapause and wild type
" Seed mixtures were less risky for WCRW IRM than ECB IRM (partially due to differences in dose, partially due to density dependent mortality in WCRW)
" Nansen discusses the possibility of marking beetles using electrostatic fluorescent powders
" Difficulty in marking sufficient numbers to recapture, possibility of artificial infestation

Resistance/toxicology
" Meinke/Siegfried  baseline susceptibility to clothianidin (Poncho) is very high, problem is having sufficient dose to affect field populations

Pollen movement
" Shields  quantifying amount of transgenic pollen that leaves field and is transported horizontally
" Survival of pollen in air can be up to 6 h (if cloudy, humid)
" Synchrony of silking/pollination in current hybrids mean that contamination is only likely for 1 day
" 100 m above ground, find 1-7 grains/cubic meter of air sampled (significant amount for transport)
" potential to move for miles, indicates that corn with traits requiring isolation cannot be grown in areas where other corn is grown

Implementation/IRM Compliance Issues
" Hurley  U of MN Ag. Economist, describes survey data that indicate that many growers who are planting refuge are doing so incorrectly (wrong size, location etc.), these data are for ECB refuge, collected by phone survey. Noted that a high percentage (10%) of growers indicated that they had been audited for compliance
" Construction of survey questions was major hurdle to obtaining informative data
" Discussion of how to determine compliance (field surveys with gene check strips vs. remote sensing of canopy differences between refuge and transgenic)

IPM/IRM for non-rootworm pests: Nick Storer requests discussion of current EPA policy of treating the entire field (including transgenic) for non RW pests
" Porter  spraying of refuge only vs. treating entire field. The issue is that susceptibles must be preserved, recommendation of the committee in the past has been to spray entire area.
" Ostlie - Silk clipping in refuge is often more severe, possibly prompting growers to treat only in refuge
" Spencer  treating the refuge does not mean you are killing off more rootworm beetles that are susceptible because of mixing and movement throughout fields

Discussion of statement of refuge compliance and Bt resistance for EPA
" Hurley  adding a statement of $ advantage would strengthen the statement
" Shields  demonstrated yield reduction under high pressure is sufficient
" Hibbard  advises using the word tolerance (vs. resistance), emphasizing that the response is increased survivorship in lab/greenhouse
" Spencer/Onstad  recommend use of terms increased survival following exposure to Cry proteins
" Statement-writing sub-committee agrees to re-work statement and distribute new version to entire NCCC46 committee by Wednesday January 30, AM
" Porter  emphasis should not be on non-compliance, but rather upon documented biology of the insect

Transgenic performance
" Ostlie  comparison of Yieldgard vs. Herculex vs. Aztec (yield benefit, lodging, root damage etc.)
" At most extreme example, Aztec yields 12 bu/acre less than Herculex  represents a significant dollar loss in planting refuge

Chemical alternatives
" Turner  review of 2006 study of clothianidin-based seed treatments on maize yield
" 2004  several anecdotal reports of yield boosts with clothianidin-treated seed
" 2005/06 objectives: Quantify yield enhancements, if any
" under low pressure, high rate of Poncho performed well in reducing damage (SD)
" in SD trials, high-rate Poncho + Force 3G led to highest yields, not significantly so
" IN data: considerable damage in Poncho 1250 plot, yield was also poor in these trials
" At some sites (MI, SD) an increase in yield was documented in Poncho 1250 treatments with zero rootworm pressure
" Overall, the group data do not support the notion of a yield enhancement with P1250
" The spectrum of damage levels and yields suggest that in some cases, yields in Poncho treatments are greater than expected by analysis of root damage
" Fuller requests permission to summarize data and move forward with manuscript development and submission
" Fuller moves to proceed to ms development and submission  motion passes, unanimous
"
" Wilde  seed treatments (Poncho + Cruiser) yield benefits study
" Estimates 75% of all corn treated with insecticide, up from 65% in 2005 and 25% in 2004
" Goal of study was focus upon non-RW areas
" No yield differences across 9 locations in KS in 2005, no differences in 8 locations in KS in 2006
" Analysis of data by location results in 72 total comparisons for 2005, only 4 of 72 comparisons resulted in significant difference
" Similar analysis for 2006, 64 comparisons result in 4 significant differences
" Of 8 significant yield differences above, 4 were high rate of Poncho treatment, but overall no consistent pattern was documented in the study (variables: location, rainfed/irrigation, hybrid effects)
" Wilde  study 2: container study (greenhouse) to evaluate same products/rates as above under greenhouse conditions
" No significant difference in leaf area, root fresh weight, plant fresh weight at 1, 2 and 5-leaf stage, comparing Cruiser, Poncho and untreated
" Conclusion: no enhanced growth effects observed

Sampling and thresholds
" Cullen  Variant sampling in southern portion of WI continues to increase, 106 fields monitored in 2006
" 10 contiguous counties of over-threshold variant counties, based upon yellow sticky trap counts
" Grower surveys indicate that growers are generally unwilling to sample own fields to make treatment decisions in 1st year corn
" Ostlie points out that industry may be co-opting yellow sticky trap counts to sell additional quantities of transgenic seed (i.e. using FFA to generate sales data)
" Cullen  goal is to move toward reduced-cost trapping (less traps, fewer locations etc.) to encourage adoption
" Working with Mitchell (economist) to develop a cost-benefit outline for trapping for the variant
"
" Glasser (US-EPA)  remote sensing of B.t./refuge areas
" 80-90% ability to categorize transgenic vs. non-transgenic (overall) using remote sensing
" analysis of infestation (ECB) was also readily apparent from these imaging techniques, preliminary results of RW infestation also encouraging
" resolution between 0.5 m  1 m, flying at 2000 or 4000 feet
" longer-term goal is using satellites for determining areas of concern (i.e. resistance development in the landscape)

Economic thresholds
" Meinke  reports that NCRW root ratings plotted vs. beetles emerging in cages (1 plant/cage) (i.e. less than 30 beetles/cage = rating of 0.25 etc) have relatively strong linear relationship

Host plant resistance
" Hibbard  cross of Bohn/Hibbard lines with elite (susceptible) germplasm, resulting in less damage than resistant line alone
" Indicates that hybrid vigor may play a role in native resistance
" Also mapping location of the genome associated with native resistance, root damage correlates with root size and root regrowth
" Approaching the point where native resistance may reach US corn market within 10 years

Other issues
" Spencer  collected volunteer corn in soybean, all was Cry3Bb1 and RR
" As triple-stack becomes more prevalent, this will become increasingly common
" Islands of transgenic plants, with extreme WCR variant pressure
" Porter  this also brings up the issue of isolating food corn, which cannot be GMO

Final Business Meeting
" Hibbard  nominates Elson Shields as secretary, motion passes unanimously
" Meinke  Time and place for 2008 meeting: St. Louis and Sioux Falls presented as options.
" Spencer  mentions that meeting within the NC region would benefit many extension, also moving meetings to period in the first week in February would allow more to attend
" Westport Complex near St. Louis is proposed as a meeting location by Hibbard
" Motion to select St. Louis as first choice is made, seconded and passed, unanimous
" Proposed dates January 30 through February 3, subject to discussion with 205. Moved, seconded, and passed, unanimous.
" Ostlie  rough draft of management guide by February 2, comments by February 23, working version by late March
" Turner  forfeits $75 fee for plaque in lieu of paying registration fees, motion is passed, unanimous
" Krupke  requests impact statements from all within 60 days of meeting for inclusion in minutes
" French  management guide sub-committee for rootworm management guide: Boetel, Shields, Krupke, Nansen, Porter
" Meeting adjourned at 5:30 PM

Accomplishments

Publications

Impact Statements

1. IMPACT: Demonstration of unexpected mating differences between WCR in refuge and transgenic corn is being used by corn rootworm scientists as an example of an IRM knowledge gap between expectations and realities of rootworm behavior in transgenic corn.
2. IMPACT: Locally variable patterns of field-scale rotation-resistant WCR activity in Illinois cornfields are used to illustrate the importance and value of monitoring local pest levels before making blanket assumptions about risk of economic injury across broad areas.
3. IMPACT: In cooperation with EPA scientists, three genetically diverse non-diapausing WCR lines have undergone several generations of selection for Bt resistance. The genetic makeup of these colonies are being analyzed and mapped. This research will provide information on the genetics of resistance evolution in corn rootworms and will benefit current and future IRM plans for transgenic corn as well as other transgenic crops.
4. IMPACT: 2006 surveys that documented relative densities of NCR emerging from first-year corn and associated level of root injury in eastern Nebraska clarified the geographic variability of NCR infestation and demonstrated that NCR injury in most first-year cornfields in eastern Nebraska was not great enough to warrant grower investment in a rootworm control technique. This information has been used by growers to make more informed NCR management decisions in 2007.
5. IMPACT: Documented that under lab conditions, successful mating can occur between the pest (NCR), and non-pest (D. longicornis) species leading to viable hybrids. If introgression between the two species occurs in the field (viable hybrid production) where the species ranges overlap (i.e., Kansas, Nebraska), then the behavior of the rootworm pest complex in field corn could potentially change in the overlap zone.
6. IMPACT: In Iowa, demonstration that microsatellites mined from sequences in a western corn rootworm expressed sequence tag (EST) database are useable as markers in population studies has opened up this convenient strategy for population genetics marker discovery in other animal species.

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Report Information

Participants

J. Spencer, C. Krupke, B. Hibbard, B. Fuller, F. Meloche, B. Eisley, R. Hammond, L. Meihls, L. Meinke, P. Mitchell, T. Sappington, W. French, B. McManus, B. Nowierski, P. Porter, L. Bledsoe, D. Onstad, E. Shields, C. Difonzo, J. Smith, T. Baute, A. Ahmad, A. Gassmann, K. Ostlie

Brief Summary of Minutes

Brief Summary of Minutes of Annual Meeting:

Thursday, January 31, 2008

Chair Joe Spencer called the meeting to order at 8:08 am.

Introductions of participants: J. Spencer, C. Krupke, B. Hibbard, B. Fuller, F. Meloche, B. Eisley, R. Hammond, L. Meihls, L. Meinke, P. Mitchell, T. Sappington, W. French, B. McManus, B. Nowierski, P. Porter, L. Bledsoe, D. Onstad, E. Shields, C. Difonzo, J. Smith, T. Baute, A. Ahmad, A. Gassmann, K. Ostlie

Local arrangements  Bruce Hibbard:
Registration fees will be $25 per day for a maximum total of $75.

Approval of minutes: 2007 minutes were approved after a Motion was submitted by B. Fuller and seconded by W. French.

Succession of Officers:
Since vice chair Christian Krupke is taking a job at the University of Guelph and will not be serving on the committee in the future, E. Shields was moved to chair for 2009. Ken Ostlie was elected as vice chair for 2009 and Ron Hammond was elected as secretary for 2009.

2009 NCCC-46 meeting:

The 2009 meeting will be held in joint with the NC-205 group in Minneapolis-St Paul during the week of 1/26/09. David Andow has volunteered to be in charge of local arrangements. NCCC-46 will meet on Monday 1/26/09 starting at 1 pm and continue through Tuesday 1/27/09. The joint overlap session will begin at 8 am on Wednesday 1/28/09 and continue throughout the day. The meeting format of the overlap session will continue to include industry participation. Key individuals from industry will be invited to participate in the joint program.

International Corn Rootworm Symposium:

Mike Gray, the current Entomological Society of America (ESA) president, is planning to organize an International Corn Rootworm Symposium in coordination with the ESA Annual Meeting in Reno next fall. The symposium is being planned around the ESA meeting theme of Metamorphosis and Change. Mike hopes to arrange for a live video feed into Europe and live interactions with European scientists who work with rootworm. Members of NCCC-46 expressed a high level of interest in participating in the symposium.

Old Business:

Management guide:

Money made available through Joe Spencer for the management guide has to be spent by June 14, 2008. It was suggested that the money be spent on publications graphics, layout and preparation charges.

Ken Ostlie mentioned that the Minnesota AES director has offered to bank roll the publication at no cost. After the web version is up and running, paper version sales are expected to be a minor amount. It was suggested that money from sales of the paper version needs to be directed to web development of the management guide.

The guide needs to be finished in the next 4 months and authors will get one more chance to update their sections. Distribution maps and good photographs are needed for the guide. Distribution maps of Western corn rootworm soybean variant and Northern corn rootworm extended diapause is needed for the guide.

Deficient areas in the management guide:
1) thresholds are 15-20 years old.
2) quoted yields are too low and old for current agriculture.
3) Poor connection between beetle numbers and damage continues to be a disconnection between scouting and treatment decisions.

State Reports:

Distribution, abundance, species composition:

Ohio: The soybean variant showed up for the first time as damage in 1 st year corn in 2007. Populations of adults are now being found in soybeans. The infested region is now a 3-county area and the variant is moving further into the interior of the state. The variant entered the state from Indiana several years ago, but only started to be a problem in first year corn in 2007. The infested counties are still located north of I-70.

Eastern Indiana : In 2007, heat unit accumulations were much higher than normal, with an extra month of heat units accumulated by the end of the growing season. The increased heat unit accumulation was responsible for earlier emergence of corn rootworm and maturity of the corn crop. Additional heat unit accumulation was also noted in Minnesota.

Ontario: An increased number of adult Western corn rootworm adults were collected on traps located in soybean fields located in southern and western Ontario. No corn rootworm problems were reported in first year corn in 2007.

Wisconsin: Southern Wisconsin is just starting to report a few Western corn rootworm beetles in soybean fields. However, the populations are not nearly the magnitude reported further east. It appears that most of the variant beetles are moving east rather than north.

Michigan: The variant appears to be spreading northeast in Michigan, but not in a contiguous fashion. Instead, there appear to be variant patches surrounding by non-variant areas. Anecdotal reports from Ohio report a similar phenomenon at the front of variant distribution, with isolated areas of damage in rotated corn surrounded by areas without damage.

Historical spread of Western corn rootworm:
Tom Sappington presented information documenting the spread of Western corn rootworm across the US. It appears that WCR started to spread in the 1940s from the western edge of Nebraska along the Colorado border. The initiation of spread eastward seems to be tied to continuous corn grown under irrigation with the use of soil insecticides. According to the information, WCR moved across the Midwest in the 60s and 70s and reached the eastern seaboard by 1990. During the spread, disjunct pioneer populations were often detected far ahead of the main front, similar to what is being seen now with the spreading rotation-resistant variant and along the spreading front in Europe.

European Introduction:
It appears that Western corn rootworm was introduced into Europe during at least 5 different introduction events. It also appears that WCR is being introduced on continuous basis.

Behavior and Ecology:

Illinois: Joe Spencer reported that WCR oviposition in non-corn habitats remains a large problem within the variant area. Calling the variant the soybean variant is a misnomer since the variant lays eggs everywhere rather than just in soybeans. In contrast, the corn variant lays eggs only in corn.

Iowa: A survey was conducted in Iowa for the variant WCR by establishing a North-South transect of sticky cards in soybean fields in the eastern third of the state. The sticky cards were changed weekly. A few adults were collected on the sticky cards but no first year damage was noted. A proposal has been submitted to expand the trapping network in 2008 to include both a North-South transect and an East-West transect. The network would include both sticky cards and egg traps. Collected data would be used to create adult distribution maps in soybeans and emergence of adults in first year corn fields.

Kansas: Very low populations of WCR were observed in Kansas in 2007. Very high rainfall in June and July during the early larval stages may have had a significant impact on the populations. Data was presented on refuge movement/dispersal. Movement within and between treatments were monitored using yellow PVC pipes treated with a sticky coating to trap the beetles.

Minnesota: Significant CRW oviposition has been observed around Roundup Ready volunteer corn in Roundup Ready soybean fields. Both NCR and WCR adults have been observed. Failure of farmers to eliminate volunteer corn from their soybean fields has both IPM and IRM implications.

Indiana: It was suggested that we should be concerned about volunteer BT corn in soybean fields. Most of the volunteer plants (87%) were Roundup resistant and difficult to control in Roundup Resistant soybean fields and 64% of the plants has the BT gene present. The BT positive plants also suffered significant larval damage therefore the assumption was that the BT dose in the plant was low. This situation has significant implications with regards to the potential development of resistance and resistance management.

Wisconsin: The current high corn prices present difficulties with the implementation of IPM with CRW management. High corn prices reduce the EIL to a level, where it is difficult to discern between the adults CRW ovipositing in the field and the adult CRW which are transient and just passing through.

Nebraska: Increasing levels of NCR are being observed in Northeastern Nebraska. The increased population is suggested to be a result of increased egg survival due to recent warmer than normal winters and the increasing presence of extended diapause. Extended diapause was documented in Northeastern Nebraska in 2004-2007. Economic losses from NCR in first year corn have not been reported to be a problem currently. A few WCR emerge from first year corn but these individuals are thought to be a representation of natural egg-laying variation (a few individuals scatter their eggs away from corn) or extended diapause in WCR.

South Dakota: The abundance of volunteer corn in soybean fields attract WCR adults and trigger oviposition around the volunteer corn plants. It is believed this is the source of the damage in first year corn rather than extended diapause or the presence of the soybean variant in South Dakota.

Dispersal and Flight Behavior:

Indiana: Research focus has been on the flight behavior of males from refuges to calling females within the BT fields. Key questions include the distances between the refuge and the BT fields and the differential timing of emergence between the refuge and the BT fields. Data suggests that mating is not random but the heavier females are selected more often by males and the heavier females are mated more often. On average, females mate only once while males mate an average of 2.5 times. Most male mating occurs before 10 days of age. After 10 days of age, male mating is rare. Most male mating occurs during a 3-4 day window within the 10 day age window. A key IRM question is How far will males disperse from the refuges during the relative small window where mating occurs?

Illinois: Research is continued to be focused on the movement of WCR beetles between corn and soybean fields. Female movement at the interface between the two crops shows significant difference in areas with and without the rotation-resistant (soybean) variant. In areas of Illinois where the rotation-resistant variant is not known to be present, 0.7%-3% of the females had soybean tissue present in their gut when trapped at the soybean-corn interface. In contrast, in areas where the rotation-resistant variant is known to be present, between 7% and 11% of the females trapped at the soybean-corn interface had soybean tissue present in their gut. It was suggested that this data could be used as a statewide screening tool to identify areas where the rotation-resistant variant was present or absent.

Host Searching Behavior:

Missouri: Feeding behavior, host searching behavior and host recognition cues will continue to be a major focus of research. A new effort will be launched with the addition of E. Bernklau to identify the chemical cues used by CRW to locate suitable roots and begin feeding on those roots.

Mating Behavior:

Illinois: Questions were raised about movement of beetles in and out of the refuge. Do males enter transgenic corn? Do females move out of the refuge? Do refuges really work? Illinois data suggests the following. 1) Males in the refuge emerge early and mate with females in the refuge. 2) Males move out of the refuge into nearby transgenic corn. Due to the relatively small window for mating by the males (10 days), too few males are available in the refuge who are capable of mating with females in the refuge and therefore the females move out of the refuge into nearby transgenic corn to mate with males in the transgenic field. Emergence of males in the transgenic field tend to lag behind the emergence of males in the refuge and this lag encourages the refuge females to leave the refuge unmated and seek out newly emerged males in the transgenic field.

South Dakota: With NCR, mating studies were conducted, comparing size advantage of both sexes to mating success. Large females mate more often, but most females mate only once. Large males are more competitive and are more successful in mating.

Rearing:

South Dakota: USDA is continuing to rear multiple colonies with varying genetic backgrounds. Current BT resistant lines have developed about a 4 to 5 fold resistance level. Fitness parameters and genetic traits of the resistant lines are being characterized.
There is currently a joint project with EPA to develop resistant lines to CRY 1Bb toxin.

Extended Diapause:

Minnesota: A change of the survey protocol by the Department of Agriculture for extended diapause has caused a few problems. The new protocol is sufficiently different that data from the old survey protocol cannot be compared to data collected under the new protocol.

Iowa: The numbers of NCR adults collected in emergence traps are increasing in eastern Iowa. This data suggests that extended diapause in NCR is becoming a bigger issue in eastern Iowa.

Nebraska: Since 2003, a large number of NCR adults have been observed emerging from 1st year corn in eastern NE. Field studies conducted between 2004 and 2007 showed the presence of 3-year extended diapause along with 2 year extended diapause. Data from Nebraska suggests that a different pattern of extended diapause is present in Mead, Nebraska compared to Pipestone, Minnesota. A 2006-2007 survey documented the variability and intensity of adult NCR emergence from first-year corn in eastern NE.

South Dakota: Studies are underway to characterize the inheritance of the extended diapause trait. Cooperative research has been initiated with Tom Sappington to identify potential genetic markers.

Host Interactions (corn vs alternate host):

Missouri: Research identifying potential NCR wild larval host has indicated that Western wheat grass and slender wheatgrass are a better larval host for NCR than maize. Larger number of larvae survived on these grass species than maize and more adults emerged. Several other species also showed good larval survival similar to maize. However, NCR has a narrower alternate host range than WCR in a greenhouse pot study.

A study has also been completed looking at the food value of dying roots of maize and the alternate host Setaria fabert. Plants were killed with roundup or severing the growing tip of maize. After 5-days, the dying roots become unsuitable as a food source.

Diabrotica Genetics: An ESA symposium on corn rootworm genetics was held at the last ESA annual meeting in San Diego.. The speaker list and topics were as follows:
Genetic markers
Tom Sapppington: Marker development
Nick Miller: Reconstructing routes of invasion
Peter Pauls: Genetic marker for the variant

Genetics of insecticide activity and resistance:
Blair Siegfried: Potential sites of the mid gut
Ken Oswald: Linkage mapping of BT resistance

BT resistance evolution:
Tim Nowatzki: Lab selection of CRY 34/35ab1 BT resistance
Lisa Meihls: Lab selection of CRY 3Bb1 and CRY 3Aa BT resistance.
Lance Meinke: Fitness of surviving WCR adults.

Wolbachia:
Georgia Davis: Maize response to infected WCR feeding.
Rosanna Giordano: Using mtDNA & Wolbachia for rootworm
phylogeography.
Rich Roehrdanz: Role in NCR reproductive isolation


Tom Sappington gave a short presentation about the common type of genetic markers (Microsatellites, ALFPs, SNPs) and their uses. The goal is to develop a set of core markers or universal panel which allows direct comparison between labs and genotype data. A set of criteria was developed and a total of 6 markers met all of the criteria for inclusion. It was suggested that these 6 markers should be used by all labs in future population genetics studies, in addition to whatever other markers might be used.

Other:

Illinois: It was reported that in field collections, melanic females are 1.19 % of the population and melanic males are 1.3 % of the population.

Management:

Minnesota: The range expansion of extended diapause coupled with the projected increase of corn prices for the next few years is providing new NCR management challenges.

Ken Ostlie tossed out the following question: If IRM is broken and IPM is on life support, how do we know how to recognize when we have resistance? A discussion followed with no conclusion.

Resistance/Toxicology:

Missouri: Work is progressing in the lab and field testing of resistance levels and the durability of the resistance in both the lab and field. Colonies are being developed to express 3-different levels of resistance. Currently, after 6 generations of constant exposure, a 17-38 fold level of resistance is being expressed. Individuals are also being tested for fitness. What is a good measure of fitness? Will one of the classical parameters work best (size, mating success, fecundity) or will a less traditional parameter be a better indicator (disease/parasite challenge)?

Implementation:

Michigan: A study was conducting at two locations, looking at the effects of the refuge structure on adult emergence dynamics. The treatments were a 10% and 20% block, a 10% and 20% strip, a 10% and 20% refuge in a bag and a 100% refuge. The emergence of transgenic males, transgenic females, refuge males and refuge females was recorded. Different refuge strategies impacted the pattern of adult emergence. It was interesting to note that the refuge in a bag emergence curve tracks the emergence curve of the refuge.

A discussion followed about the tradeoffs between larval movements between transgenic and non transgenic plants giving increased selection vs impact on adult mixing at mating with blocks or strips due to physical separation

Refuge/IRM Compliance:

Canada (Ontario): Grower compliance was disappointing. New corn growers seemed unaware of the refuge requirements while traditional corn growers have a higher level of compliance.

A discussion followed about compliance in the different areas. Minnesota survey results indicated compliance is in the range of 60-70 percent. Indiana compliance was felt to be in the 60 percent range . West Texas in Pat Porters area was planted to 80+% BT corn when the requirement was 50% refuge. Illinois: Joe Spencer feels that the compliance is lower than reported. Nebraska: Compliance is felt to be much lower than required.

IRM vs IPM:

Billy Fuller: The crisis has not occurred to encourage continued use of IPM. When the crisis occurs, farmers will come for the answers and new crisis solving strategies. With the low level of IRM enforcement, what is the cost of breaking compliance rules?

Economic Threshold:

Minnesota: At this point in time, Ken Ostlie feels that we have no valid economic threshold data to work with, due to increasing yield, changing technology, increasing beetle numbers. The issue of economic thresholds needs to be reexamined. Are thresholds for insecticides still appropriate for the new technologies and yields?

A discussion followed:
Billy Fuller: It seems that the large number of adults emerging from a single resistant plants do not reflect the expected root damage and resultant yields.

Joe Spencer: Above ground symptoms of the damaged plants do not reflect the level of root damage.

Ken Ostlie: Difference in root mass seem to be variety related. Plant population also impacts the root mass. In addition, soil moisture has also a big impact. Root regeneration is yield related and may or may not have a positive yield impact. Triple stack affects the overall plant health because of root protection. Increased nitrogen uptake in the triple stack may be from the root protection.

Discussion followed about the role of seed treatments on the plant. Seed treatments will have damaged roots, but the root damage is not reflected in a equal yield loss. Under high pressure, we do not have the tools to protect the refuges and protect the farmers from yield losses in the refuges.

What can we do to reduce the overall CRW area pressure to allow all of the technologies to work better. Nebraska: Soil insecticides and seed treatments have not always held up under the very high pressures. Furadan has been used as a rescue treatment in these situations, but it looks like the EPA is going to deny re-registration of Furadan in corn. We are losing tools in our insect control tool box. Technology is moving too fast to be proactive, we are in the reactive mode and we have to work with the consequences. Research is currently more defensive or reactive than proactive. EPA and industry has isolated this group from the decision making process.

What can we do to make this committee more relevant to the process? How can we raise awareness to the issues? Do we want to prepare a white paper? What is the real issue? Do we want to submit a forum paper for a Nature Biotechnology paper or a JEE paper to draw attention to the issue about transgenic issues. Also cover exclusions from the process. What do we need to do for the public benefit?

Ken Ostlie: Where we are in transgenic adoption, resistance management, and biological impact arena? Industry controls the seed supply therefore controls research and scientific objectivity. Even commercially available seed lines are prohibited from use in scientific investigations by the technology agreement which is required to be signed before the seed is delivered. The greatest impact is on scientific objectivity and impacts our charge as scientist employed within our Agricultural Experiment Stations. What role can ESA play to support this effort?

Wide interest was present across the committee to pursue the issue of a paper/journal article with an outline. Ideas will be circulated. Joe Spencer and Tom Sappington will head the effort and circulate the ideas and outline.

Attempts will be made to include as many NCCC-46 participants as possible as authors, although it is understood several may not be able to participate or include their names for various reasons. There was discussion about whether to include other groups like NC-205 and the cotton research community, but no conclusion was reached. This issue will be revisited once the initial outline is prepared.

Root Rating Injury Scale:

A discussion was conducted on the issue of the 1.5 inch criteria for damage assessment with the Iowa 0-3 scale. The question was raised if the 1.5 inch limitation of damage really covered the impact of the feeding damage on the outer root system. Ken Ostlie suggested that the 1.5 inch evaluation was a better predictor of lodging than the 3 damage evaluation but may not be applicable to yield impacts.

Host Plant Resistance:

Missouri: A new variety has been released with a high level of resistance to CRW larval feeding. Parentage is a combination from a lot of tropical sources. A polygenic source of resistance and mode of action is suggested. In addition, there is a possible new source of germplasm from the Colorado corn breeding program.

Resistance to insecticides:

Indiana: The level of CRW control with Force soil insecticide appears to be more erratic in Indiana then in past years. The question is why the increased erratic level of control?

Nebraska: Adult control programs using aerial spraying are still occurring in far western Nebraska, eastern Colorado and western Kansas. Blair Siegfried still has an active IRM research program. He is currently looking at the mechanisms of resistance to Organochlorines and Organophosphates, in addition to his BT resistance work. Blairs lab group is identifying molecular markers to identify resistance genes. Blair may also be looking for cooperators to collect beetles from specified geographic locations for his research. He is also interested in using resistance associated molecular markers to possibly help identify sources of WCR that were introduced into Europe.

Trap cropping:

Illinois: A project was initiated in 2007 to look at the concept of trap cropping as a way to improve the management of CRW. In the concept of Trap then manage the rootworm, if the eggs could be concentrated into a smaller area of the field, then the use of transgenic corn could be concentrated into smaller areas. The rows of corn used as a trap crop was planted in a soybean field. Not surprising, the 2007 information showed the CRW adults concentrating in the corn strips. Joe Spencer is looking for a Ph.D student to work on this study. Information will be forthcoming in the near future.

Indiana: A trap cropping project was also initiated in Indiana using a runty mutant corn selection which is very attractive to CRW adults. The adults really hammer it with feeding damage. The corn breeder at Purdue is looking for possible cooperators.

Rotation:

Minnesota: A long-term rotational study has been initiated using a 5-year rotation cycle. The focus of the study is to look at the rotational effect and the benefit from triple-stack vs. the double stack as subplots within the rotation blocks. This study is being conducted in an area with NCR and extended diapause.

Other soil insect issues:

Ontario, Canada: Increasing damage being reported in Ontario from millipedes for the past several years across a number of crops. Researchers are currently looking for funding to evaluate the impact of millipedes on corn.


Final Business meetings:

Ron Hammond was nominated for Secretary and Ken Ostlie was nominated for vice chair. The members of the project elected these two individuals with a unanimous vote.

The 2009 meeting will be held in joint with the NC-205 group in Minneapolis-St Paul during the week of 1/26/09. David Andow has volunteered to be in charge of local arrangements. NCCC-46 will meet on Monday 1/26/09 starting at 1 pm and continue through Tuesday 1/27/09. The joint overlap session will begin at 8 am on Wednesday 1/28/09 and continue throughout the day. The meeting format of the overlap session will continue to include industry participation. Key individuals from industry will be invited to participate in the joint program.

Start time for NCCC-46 will be 1 pm on Monday 1/26/09 unless other issues suggest an early meeting session on a specialized subject.

Dennis Calvin is the current chair of NC-205 for the next year in 2009 meeting.


Question to the committee membership: Do we want to think about a publication about joint refuge issues between ECB and CRW?

Management Guide: There will be a final push toward publication. Editorial changes need to be made, pictures collected and graphics developed. There will then be one final opportunity for NCCC-46 members to comment on the publication before it goes to press. The insecticide section is missing. The insecticide section will be edited by the writing committee before the final draft is moved to layout.

Impact statements are needed from the membership for the minutes. Please submit them to E. Shields.

Meeting was adjourned at 11:56 am on February 1, 2008.

Accomplishments

Publications

Impact Statements

1. Ongoing Illinois study demonstrated that mate-seeking refuge WCR males thoroughly disperse into transgenic corn. In addition, unmated refuge females are also dispersing into transgenic corn seeking a mate. This information supports movement assumptions integral to WCR IRM strategy.
2. Locally variable patterns of field-scale rotation-resistant WCR activity in midwestern corn fields illustrate the value of monitoring local pest levels before making blanket assumptions about risk of economic injury across broad areas.
3. 2006-2007 surveys that documented relative densities of NCR emerging from first-year corn and associated level of root injury in eastern Nebraska clarified the geographic variability of NCR infestation and demonstrated that NCR injury in most first-year cornfields in eastern Nebraska was not great enough to warrant grower investment in a rootworm control tactic. This information has been used by growers to make more informed NCR management decisions in 2007-2008.
4. USDA is continuing to rear multiple colonies with varying genetic backgrounds. Current BT resistant lines South Dakota have developed about a 4 to 5 fold resistance level. In Missouri, after 6 generations of constant exposure, a 17-38 fold level of resistance is being expressed. Fitness parameters and genetic traits of the resistant lines are being characterized. There is currently a joint project with EPA to develop resistant lines to CRY 1Bb toxin. This research will provide information on the genetics of resistance evolution in corn rootworms and will benefit current and future IRM plans for transgenic corn as well as other transgenic crops.
5. Development and international agreement on a standard core set of microsatellite genetic markers for WCR has made it possible to directly compare results and share data across different laboratories and across time. Use of this standard set of markers already is accelerating research on WCR population and invasion genetics in the US and Europe.
6. USDA-NCARL rearing of the WCR colonies from different Corn Belt regions and with different characteristics of resistance is a valuable tool for research into pest genetics and resistance evolution. Use of these colonies has been instrumental in several recent studies. USDA foresight to establish and maintain these colonies is enabling comparative research that has contributed to greater understanding of resistance, population dynamics and pest behavior.

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Report Information

Participants

Baute, Tracey (tracey.baute@ontario.ca) - Ontario Min. of Ag
Bledsoe, Larry (lbledsoe@purdue.edu) - Purdue University
Boetel, Mark (mark.boetel@ndsu.edu) - North Dakota State
Cullen, Eileen (cullen@entomology.wisc.edu) - Univ. of Wisconsin-Madison
Difonzo, Chris (difonzo@msu.edu) - Michigan State University
Eisley, Bruce (eisley.1@osu.edu) - The Ohio State University
French, Wade (wade.french@ars.usda.gov) - USDA, ARS
Gassmann, Aaron (aaronjg@iastate.edu) - Iowa State University
Hammond, Ron (hammond.5@osu.edu) - The Ohio State University
Hibbard, Bruce (bruce.hibbard@ars.usda.gov) - USDA-ARS, Columbia, MO
Mason, Chuck (mason@udel.edu) - University of Delaware
McCornack, Brian (mccornac@ksu.edu) - Kansas State University
McManus, Brad (bradley.mcmanus@sdstate.edu) - South Dakota State Univ
Meinke, Lance (lmeinke1@unl.edu) - University of Nebraska
Ostlie, Ken (ostli001@umn.edu) - University of Minnesota
Porter, Pat (p-porter@tamu.edu) - Texas A&M
Potter, Bruce (bpotter@umn.edu) - University of Minnesota
Sappington, Tom (tom.sappington@ars.usda.gov) - USDA-ARS, Ames, IA
Siegfried, Blair (bsiegfried1@unl.edu) - University of Nebraska
Shields, Elson (es28@cornell.edu) - Cornell University
Smith, Jocelyn (jsmith@ridgetownc.uoquelph.ca) - University of Guelph
Spencer, Joe (spencer1@illinois.edu) - University of Illinois
Tollefson, Jon (tolly@iastate.edu) - Iowa State University
Tooker, John (tooker@psu.edu) - Penn State University
Pueppke, Steve (pueppke@msu.edu) - Michigan State University

Brief Summary of Minutes

Monday, January 26, 2009

Elson Shields welcomed everyone to the meeting and mentioned that the agenda should be in everyones hands. He commented about the external meeting on Tuesday night with industry folks from Dow and then Pioneer.

Dave Andow discussed the local arrangements for the meeting. He welcomed us to Minnesota. He first talked about the projection system set up. The meetings on Tuesday night will be at the University. He brought up the idea of an organized dinner for Monday, which most of the group supported. Registration fee for this meeting will be $100. If staying for the joint meeting, the cost will be $150. If staying over for the NC205 meeting, the cost will be $200. Continental breakfast will be provided each morning in the meeting room.

Elson then asked for everyone to introduce themselves.

Steve Pueppke gave an administrative update. NCCC46 is going through a mid term review. Next year the group should be getting involved in the rewrite of the committee. He mentioned that this is the year of a new farm bill which includes some major reorganization of the groups that support groups such as ours and the NRI program. A lot of money will be going towards competitive funds rather than formula funding. There is a push to bring agricultural research up to the same level as NSF or medical funding. Steve asked if there were any questions.

Elson brought up the minutes from last year, and asked for approval of them. They were approved unanimously.

A nomination committee was selected. The group was Joe Spencer and Mark Boetel. The group will need to identify a new secretary for 2010. Ken Ostlie was thanked for his willingness to step in as the new chair. Elson than asked for members to be a site selection committee. Pat Porter and Eileen Cullen volunteered. Both Madison, WI, and Columbus, OH, were discussed.

Future meeting format and meeting with NC205. The committee should discuss over the next few days and it will be brought up later during the meeting.

Management Guide for Corn Rootworms.  Joe Spencer discussed the current status of it. The guide is at the point where they have passed it along to a publication office. Ken Ostlie thanked all those who provided photos for the guide. There are still some photos that are missing. Ken discussed what will happen in the near future with final approval. Ken hopes to have a finished copy around the NC Branch meeting. He then discussed the various ideas for circulating the guide, and what to do with any funds brought in from its sale.

Jon Tollefson discussed Marlin Rice leaving ISU within the next few weeks for a job with Pioneer.

Lance Meinke mentioned that Gary Hein will be leaving the western NE location and moving to Lincoln for a new position. His old job is opening up for a replacement.

State Reports

Bruce Hibbard said that he had a CD of state reports. He sent copies around for people.

Distribution, abundance, and species composition

IL  Joe Spencer said they had high adoption of transgenic corn. He observes that there seems to be a general decline of rootworms across the state.

IN  Larry Bledsoe said they have seen a general decline also, although he does not think its necessarily related to the amount of transgenic corn. He thinks there are a lot of environmental conditions that might be causing it. He saw a generally late population this past summer.

IA  Jon Tollefson said that the variant is in generally in the east side of IA by Dubuque and around the Quad Cities. Tom Sappington discussed the expansion of the WCR across the country and in Europe and pointed out two new reviews: Gray et al. 2009 Annu. Rev. Entomol. 54: 303-321; Meinke et al. 2009 Agric. For. Entomol. 11: 29-46. Both have thorough discussions of history and dynamics of the expansions, and Gray et al. also has several good maps.

KS  Brian McCornack said that populations were low this year.

MI  Chris Difonzo said they were low, with variants in a localized area in central MI.

MN  Ken Ostlie also saw lower numbers, with a shift in some places towards northerns. They discussed some of the relationships between westerns and northerns in the state.

MO  Bruce Hibbard discussed the situation in the state, without any specific comments on populations.

NE  Lance Meinke talked about the wet and cold weather, and the subsequent lower numbers. Western NE had some higher numbers. Northerns are still high in northeast Nebraska.

NY  Elson Shields said that there was little economic damage in the state.

ND  Mark Boetel stated that NCR has been the predominant species observed in informal surveys in ND during the past few years. . Populations are concentrated in the southeastern portion of the state.

OH  Ron Hammond and Bruce Eisley said that the variant has gone farther south and east into Ohio, below I-70 and into central OH north of Columbus towards the north.

PA  John Tooker said they were generally low.

SD - Brad McManus said that dry areas were higher with wet areas low, with a lot of northerns being observed.

TX  Pat Porter said that Mexican corn rootworms were general low, although southern corn rootworm appeared in some places.

WI  Eileen Cullen said that the two species are about 60:40 WCR:NCR in state. CRW pressure in UW Madison efficacy trials is heavy each year because we trap crop the field sites (plant corn late June of previous year to have pollen/silks to attract egg-laying adults). CRW pressure in commercial fields (continuous, normal May corn planting dates) varies from year to year. CRW damage reported each year. Increasing attention to CRW damage in corn silage growing areas in eastern WI. WI Association of Production Ag Consultants reported to Cullen lack of efficacy on CRW trait (Agrisure, and anecdotally other brands). Some consultants and growers are adding soil insecticide to transgenic corn, especially those from Agrisure. They also saw lower pressure of the variant western corn rootworm this past year in Wisconsin. No trapped fields in the WI Dept. of Agriculture pest survey reached threshold, all soybean fields trapped with 12 Pherocon yellow sticky traps were far below 5 beetles/trap/day economic threshold (i.e. below 1 b/t/d). She shared with the group various extension publications they produced.

Ontario  Tracey Baute reported they were normal or maybe even slightly higher in terms of general pressure, and that Poncho 1250 did not work well. The variant is not that high generally in the province yet except for one location or pocket.

Behavior and Ecology

IL  Oviposition studies were conducted with beheaded beetles. Beheaded females generally oviposited eggs rapidly. 32% of beheaded females had ruptured oviducts. Discussed some of their observations of mating for insects from transgenic and refuge corn. Numerous committee members joined in a discussion of what has been seen by others on mating- and dispersal-related issues.

MN  looking at volunteer corn issues, which will be discussed under management.

NE  looking at differences between two different species barberi and longicornis knowing that they have a good overlap in their range. They were doing this especially with mating behavior.

SD  mating behavior studies are finishing.

Brain McCormick asked if there are some basic behaviorally or ecological items that are not being addressed that should be. Tom mentioned long range dispersal as an area of interest. Ron Hammond mentioned that OSU has a new person, Mary Gardiner, who is a landscape ecologist who wants to work with specific pests and how it can impact management of those pests.

BREAK

Biology

IL  Has observed some color differences of WCR. A melanic color variation is about 1% of the population. In Europe, its a lot higher. Genetic studies have been initiated. Also are conducting some studies and beginning to consider what might happen if additional host plants of rootworms are grown for biomass for biofuel uses. He is specifically working with Miscanthus gigantueus.

IA . Aaron (IS) is beginning studies with various colonies of the different species and types. Sappington discussed aspects of population genetics and potential long range dispersal. There was an active discussion on various aspects of this area. The findings so far suggest WCR across the U.S. are similar genetically speaking. He also discussed some work they have done in Europe with the WCR. They have been able to conclude that there were five independent introductions in Europe. He passed out information on a recent WCR genome sequencing workshop that was held in Reno, NV, and what was discussed.

MO  Discussed some of the publications forthcoming and over the past year on research of the biology of rootworms.

NE  Attempting to better examine extended diapause of NCR.

SD  Discussed some studies with mating of regular and extended diapausing NCR. Discussed some issues that have come up with APHIS when shipping insects of different genotypes, diapausing, rotational resistant, etc. Various permits will be required in the future when shipping these various insects.

Adjourn for the day. The group decided to begin at 8:30 AM on Tuesday. The group will meet at 5:45 PM for dinner.

Tuesday, January 27, 2009

Elson Shields began by discussing some other items or issues that could be brought up after finishing the state reports. Perhaps we could being talking about the rewrite, and discuss some issues that could be brought up during the joint meeting with NC205.

Management

IL  Discussed a trap crop project that they are working on using late planted corn in strips planted into soybean fields. The idea is to trap crop the WCR variant in these areas. General finding was that trap crops did not work very well or as intended for what would be needed on large grower fields.

IN  Bledsoe told of a a graduate student looking at a 10-20% refuge in the bag strategy who is currently processing most of the data. They did not see the temporal shift when using the refuge in bag strategy compared to the normal strategy. They saw damage to neighboring corn plants next to non-transgenic plants, resulting in lesser yield. Also, they are doing work trying to sample the variant beetle by different means, including examining beetles for soybean feeding.

IA  Tollefson discussed research by Gassmann in which insecticide treatments on transgenic corn studies were conducted. Improvement in root protection was very slight, and even then, from very little injury to even less injury. Tollefson has been looking at rootworm tolerance in European corn hybrids because they cannot use transgenic nor afford soil insecticides. There are differences in tolerance with some of their varieties.

KS  Did similar studies with transgenic and soil insecticides, but had very little damage in their studies.

MI  Looking at the secondary soil pests, including many of the grub species that seem to be getting worse. A question was brought up about the winter cutworm.

MN  They are doing various studies with transgenics, volunteer corn, and crop rotation. They discussed various surveys about transgenic use and compliance with IRM requirements. Mentioned their overall transgenic performance trials, including transgenics plus soil insecticides. Then they discussed the issue with the diapausing NCR problem in the state. They also mentioned their studies on the role of volunteer corn with the two rootworm species, and whether the corn influences egg laying. Had a lot more WCR beetles in the fields with higher levels of corn; was not as evident with NCR. Results show that the greater the beetle activity, the lesser the yield. Discussed efficacy studies with the various Bt events. There appears to be some differences between WCR and NCR control, with NCR being poorer. They finished discussing their studies on transgenic plus insecticides.

There was a general discussion about the performance of Agrisure . There are some instances where the material does not perform as well as the other two transgenic families.

MO  discussed the work with rootworm resistant colonies, and then their studies with feeding stimulants. They are looking for native resistance to rootworms in corn, including having released a population of native resistant corn. Some of these lines have been shown to have antibiosis.

The committee went back to some information from Iowa, in terms of looking for the variant in eastern parts of the sate, and the diapausing NCR in the next group of counties to the west. The variant is currently in the far NE and EC parts of the state. He then discussed some concerns with the yellow traps, and research when applying soil insecticides to transgenics.

NE  a report was given on their studies looking at late season dynamics of WCR with transgenic corn. They also reported on using RNA interference techniques to examine useable genes within the insect as it might relate to resistance. Also are looking at cyclodine resistance as a marker for understanding the population dynamics and movement of WCR.

OH  talked about a students work with late planted corn using both long and short maturity hybrids. As part of that, they also looking at silk feeding from adult WCR and JP. Then they discussed efficacy work with transgenics.

TX  Doing southern corn rootworm efficacy trials with transgenics. They reported that a lot of work is being done on silage work, mainly because there is an increase in dairies in the state. NY mentioned earlier work in that state on silage corn.

WI  Reported on work with soil insecticide on transgenics, and how you seldom see improvements in root ratings but often see a very slight improvement on yields. Also, they are looking at the economics of using insecticides and transgenics as insurance treatments.

Ontario  Talked surveying growers compliance with IRM requirements in the province, and their interactions with their government regulatory agencies on future IRM policies. They are still seeing the odd millipede issue on corn seed.

Lance Meinke asked about what is happening with fiprinol (Regent) as an infurrow soil application treatment, and the possibility of loosing it. Numerous comments were made.

The committee then broke for lunch, with the afternoon session beginning at 1:15 PM.

Elson asked if there are any additional information for the state reports. Potter discussed a bimodal peak he sees with WCR in volunteer corn.

Tom Sappington mentioned the problem with not being able to get seed from companies. The publication committee of ESA is developing an ethic statement that anyone publishing in ESA journals would have to make all materials available to anyone who wants to repeat those experiments. The issue was discussed on how it would or might work.

Ken Ostlie brought up a discussion on the future of CRW management. With so much transgenic use as insurance, how do we position ourselves for these changes? How do we position ourselves to deal with possible resistance? What are the relationships between the companies, EPA, USDA, universities research and extension, etc.? The committee discussed the idea of a letter to the companies about some of these concerns, which had been discussed at last years meeting. Could any of this be made part of the rewrite for NCCC46? Elson asked if there is interest in drafting a letter. As during last years meeting, this issue was discussed in detail. Should we include constituent groups like the corn grower associations and others to get involved in this? Should we write a letter? Should we write an article/journal paper for ESA, perhaps the Forum section of JEE? Perhaps any such paper or group of papers should also bring in the views of EPA and ABSTC. This will be brought up and discussed in our joint meeting tomorrow with NCR205. Pat Porter, Tom Sappington, and Mark Boethel will take the lead and develop an outline of a possible paper, meeting this evening to jot down some thoughts and ideas.


Business Meeting

Nomination committee selected Eileen Cullen as the new secretary. She accepted.

The site selection committee selected Madison, WI. Approved. Target the same last week in January, 25-29, 2010 with NCR46 being Jan 28-29 after NCCC205. Moved and approved. Will need to determine NCCC205 interests in having the joint meeting.

BREAK

The committee then began a discussion of the rewrite that will need to begin next year.

Modified Objectives for the next rewrite.

1. Evaluate registered and experimental corn rootworm management tactics (including rootworm-resistant transgenic hybrids) for their impacts on rootworm biology and implications they may have on the agroecosystem throughout the United States and Canadian corn growing regions.

2. Coordinate a national research investigation into reported yield enhancements associated with new insecticidal seed-coat in the absence of corn rootworm injury. (Lance: this one is pretty much completed. Fuller is summarizing the data.)

3. Systematically design and implement research on rootworm mating, dispersal, survival, and host range across environments and production systems.

4. Characterize the impacts of gene flow on the spread of behaviorally and physiologically resistant pest strains and the resulting needs for designing resistance management plans. These research needs may be identified by and used in resistance-management computer simulation models.

5. Investigate the biology and impact of emerging and/or secondary below ground pests on corn hybrids and evaluate management options.

6. Facilitate national and international information exchange on corn rootworm management as it relates to other crop management practices, agroecosystem and regulatory issues.

7. Develop and maintain a public website that collates current knowledge on rootworm biology and management across regional production systems.

8. On an as-needed basis, publish statements that draw on published research and the expertise of the committee to address critical issues pertaining to existing or emerging insect control technologies.

9. (new) Evaluate the impacts of below-ground pests on plants grown for biofuels or feedstocks.


It was again mentioned that there would be a meeting with Dow and then Pioneer this evening is in Amundson Hall, Room 124, at 7:30 PM. This is a separate meeting from NCCC046.

The meeting then adjourned.

Accomplishments

The NCCC-46 publication "the corn rootworm management guide" is in final layout production and is scheduled for publication in 2009. <br /> <p><br /> A reconstructed history of WCR range expansion through North America was finished, resulting in first accurate and updated map in 25 years. <br /> <p><br /> In cooperation with EPA scientists USDA-NCARL have selected three genetically diverse non-diapausing WCR lines, which have undergone several generations of selection for Cry3Bb1 resistance. The genetic makeup of these colonies are being analyzed and mapped by the EPA. The resistant lines have developed about a 6.5 fold resistance level.<br /> <p><br /> Field and lab studies of WCR mating dynamics indicate that there is assortative mating, with large females being preferred by males. There was no evidence of any effect of male size upon mating patterns. This information is important because female weight has been shown to be both positively and negatively affected by exposure to Bt toxin, depending on exposure time, duration, and density.<br /> <p><br /> Male WCR mated an average of 3.5 times during their lifetime when given continuous access to unmated females. However, "old" males (more than 10 days after initial mating), usually did not mate at all. This is critical information to assess the success of the Bt/refuge concept, as the models currently assume that males are able to mate equally well from eclosion until death. <br /> <p><br /> Demonstration of egg-to-adult WCR development on Miscanthus x giganteus (candidate feedstock crop for the cellulosic ethanol industry) raises questions about the suitability of this perennial grass for Corn Belt cultivation. Failure to assess the capacity of Miscanthus to become a reservoir for pest rootworms, could compromise corn pest management. Uncertainty about WCR interactions with Miscanthus in the field warrant caution before promoting the widespread cultivation of an alternate WCR host on 7 million acres.<br /> <p><br /> Wisconsin entomological field research continued during summer 2008 to collect a third and final experiment year from 5 case study farms. Data for Obj. 1 and 2 of a current USDA CSREES North Central Region IPM project (Cullen and Mitchell) are fulfilled by Variant WCR trapping data from non-corn crops paired with first year corn root ratings and insecticide or Bt corn rootworm hybrid treatment strip trial yield measurements (PI, Cullen) and economic analysis (Co-PI, Mitchell) from the same fields the subsequent year. A total of 18 fields (14 soybean, 4 winter wheat stubble) were sampled across the four on-farm study sites. None of our case study farms grew alfalfa in 2008. 12 yellow sticky traps were placed in an evenly spaced grid in each field during the last week of July. Traps were checked, WCR beetle numbers totaled, and traps replaced every 7 to 10 days. The sampling period extended 6 weeks, and traps were removed in early September. Total beetles/trap/day (B/T/D) was calculated for each week interval, the entire 6 wk sampling period and for each individual trap location within each field. Additionally, during summer 2008, 21 first year corn fields in Rock and Walworth Counties that were trapped as non-corn crops (soybeans and wheat) in 2007 for Variant WCR were evaluated by root injury ratings from replicated CRW treatment efficacy (soil insecticide or Bt corn rootworm hybrid) and yield strip trials to evaluate preceding crop, Variant WCR numbers in relation to the 5 B/T/D economic threshold for first year corn, and treatment efficacy and economics by first year corn management decision paradigm. This project has now obtained IPM non-corn crop scouting data- first year corn treatment decision efficacy and economic data for two complete cycles 2006-2007 and 2007-2008, respectively. The 18 soybean and wheat fields trapped in 2008 will be evaluated in 2009 as first year corn fields to complete a third 2008-2009 data set. During the remainder of this project, Mitchell and Cullen will be analyzing experimental data to identify the most profitable combinations of Variant WCR scouting protocol, economic threshold, and crop rotation.<br /> <p><br /> Extension PRODUCTS fostered by this project include incorporation of the Variant WCR trapping survey network into the WI Department of Agriculture Trade and Consumer Protection (WDATCP) Pest Survey http://pestbulletin.wi.gov/ leveraging USDA CSREES NCIPM funding and research/extension efforts into a self-sustaining state IPM monitoring program. An Extension publication is in preparation by Cullen to communicate project findings to growers and crop consultants. Mitchell developed an initial Spreadsheet Decision Aid titled "Calculate Your Net Benefit and Break-Even Probability for Western Corn Rootworm Control Using Soybean Trap Counts" http://www.aae.wisc.edu/mitchell/extension.htm.<br /> <p><br /> 2006-2008 surveys that documented relative densities of NCR emerging from first-year corn and associated level of root injury in eastern Nebraska clarified the geographic variability of NCR infestation and demonstrated that NCR injury in most first-year cornfields in eastern Nebraska was not great enough to warrant grower investment in a rootworm control tactic. This information has been used by growers to make more informed NCR management decisions in 2007-2009.<br /> <p><br /> Volunteer corn in soybeans following triple-stack corn in Indiana was found to express glyphosate-tolerance 85% of the time, and Bt (Cry3BB1) 65% of the time. Of the plants expressing Bt, about a third exhibited high levels of damage from larval WCR feeding, indicating that expression of toxin may not be as high in the non-hybrid volunteer corn. This represents a novel food source for WCR larvae in soybean fields and should be aggressively treated with herbicide early in the year to minimize RW exposure to potentially lower toxin levels.<br /> <p><br /> Ongoing Illinois study demonstrated that mate-seeking refuge WCR males thoroughly disperse into transgenic corn. This information supports general movement assumptions integral to WCR IRM strategy. However, significant movement of unmated females from refuge into transgenic corn (perhaps related to low male density in refuge) suggests that some assumptions about refuge function are not being met.<br />

Publications

Impact Statements

1. Research and Extension components of this project are expected to result in grain producer and agricultural professional adoption of IPM treatment decision guides leading to 1) economically justified corn rootworm treatment costs and yield protection in areas affected by variant western corn rootworm; and 2) avoidance of negative economic and environmental impacts associated with insurance treatment of first year corn in absence of scouting data.
2. Patterns of stratified dispersal resulting in formation of satellite populations ahead of the main front of the WCR range as it spread across North America were recognized in evaluation of historical literature. This kind of dispersal results in an acceleration of rate of spread over simple diffusion along the front. This information has revealed the importance of eradicating satellite populations as the species spreads across Europe to slow its expansion. It also will help parameterize models of the ongoing expansion of the rotation-resistant variant across the U.S. Corn Belt.
3. USDA-NCARL rearing of the WCR colonies from different Corn Belt regions and with different characteristics of resistance is a valuable tool for research into pest genetics and resistance evolution. Use of these colonies has been instrumental in several recent studies. USDA foresight to establish and maintain these colonies is enabling comparative research that has contributed to greater understanding of resistance, population dynamics and pest behavior.
4. Because of their expertise, seven NCCC-46 scientists were invited to serve as part of a joint U.S.-European Expert Group on Western Corn Rootworm Ecology to identify research needs and draft a coordinated European research plan, EU Programme FP6-2004-SSP-4, "Harmonise the strategies for fighting Diabrotica virgifera virgifera" Aug. 2006 - 2008. Europeans recognized that American entomologists had many years of research experience with WCR ecology, and our role was to summarize for them state of the art knowledge and identify gaps in understanding that might be useful in their management of this insect still spreading through Europe. Recommendations were incorporated as part of the EU research plan.

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Brief Summary of Minutes

See attached copies of minutes.

Accomplishments

Outputs: In cooperation with industry representatives, several members of the NCCC46 committee were instrumental in composing a draft agreement with American Seed Trade Association that will allow more flexibility and transparency for researchers working on commercialized GM plants. Publication in GM crops summarizes committee views and progress on this issue (see publications section).<br /> Corn rootworm management guide: Draft version completed. Final copy will be submitted for publication in 2010.

Publications

Attached, please see publication co-authored by several NCCC46 members and led by Tom Sappington. This publication both summarizes the problems with the previous restrictions for public sector research on commercialized GM crops and outlines progress made (led by entomologists) in forging a new agreement between public sector researchers and industry. It is hoped that the new principles will be widely adopted by industry and allow researchers from a wide variety of disciplines to conduct research on these important crops with greater freedom.

Impact Statements

1. Multi-year data comparing Variant western corn rootworm trap counts from soybean with first year corn root node-injury and yield response, revealed that growers using the soybean trapping protocol and economic threshold of 5 beetles/trap/day for treatment decision support in first year corn would make a correct decision 75% of the time (treat/no-treat). 17% of fields had damage higher than predicted (treatment should have been applied although scouting indicated pest was below threshold) and 8% of fields had lower than predicted damage (treated when not economically necessary). Economic analysis of these outcomes will determine farmer profitability of scouting-based vs. prophylactic treatment. Information will be used to develop more cost-effective Variant monitoring protocols while retaining reliable treatment decision support.
2. Non-transgenic refuges in rootworm-resistant Bt transgenic corn provide locations for susceptible rootworms to develop without exposure to Bt. The refuge strategy for rootworm-resistant Bt transgenic corn assumes beetles from refuge will enter transgenic corn and mate with potentially-resistant individuals. Observation and collection of mate-seeking and mating WCR adults in refuge blocks and adjacent transgenic corn rows indicated that assumptions about limited pre-mating female movement, male mating activity, and movement rates are not accurate. The contribution of refuge male mating activity is likely not as extensive as assumed based on the WCR literature. The trend toward more integrated refuge designs (in-field refuge strips and seed blends, a.k.a. refuge in a bag) will promote desired movement and pairings between refuge males and transgenic corn females, and slow the development of resistance to Bt transgenic corn.
3. A proposed biofuel/biomass crop, Miscanthus x giganteus, was found to be a host for egg-to-adult development of the most significant U.S. corn pest, the western corn rootworm. If widely planted as a cellulosic ethanol feedstock, Miscanthus x giganteus would be grown in proximity to rotated corn and soybean over a vast area. The pest management consequences of introducing this perennial WCR host into the Corn Belt are unknown. This research result highlighted many unanswered questions about the appropriateness of Miscanthus x giganteus as a biomass crop and drew needed attention to the pest management issues for a crop often depicted as relatively pest-free. Multiple Miscanthus x giganteus growers in Illinois have contacted the authors to collaborate on monitoring that will measure pest and wildlife impacts on new and established biomass plantings and enable realistic estimates of IPM expenses in biomass crops.
4. USDA, ARS-NCARL in Brookings, SD rearing of the WCR colonies from different Corn Belt regions and with different characteristics of resistance is a valuable tool for research into pest management and biology. Use of these colonies has been instrumental in several recent studies. USDA foresight to establish and maintain these colonies is enabling comparative research that has contributed to greater understanding of pest genetic, Bt resistance, population dynamics, and behavior.

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Baute, Tracey (tracey.baute@ontario.ca) -OMAFRA, Ontario CANADA; Bledsoe, Larry (lbledsoe@purdue.edu )-Purdue University; Boetel, Mark (mark.boetel@ndsu.edu) - North Dakota State University; Coates, Brad (brad.coates@ars.usda.gov)-USDA ARS Ames, IA; Cullen, Eileen (cullen@entomology.wisc.edu) - University of Wisconsin-Madison; DiFonzo, Chris (difonzo@msu.edu)-Michigan State University; Estes, Ron (restes@illinois.edu)-University of Illinois; Frank, Daniel (Daniel.Frank@ars.usda.gov ) - University of Missouri; French, Wade (Wade.French@ars.usda.gov )-USDA ARS Brookings, SD; Fuller, Billy (Billy_Fuller@sdstate.edu)-South Dakota State University; Gassmann, Aaron (aaronjg@iastate.edu)-Iowa State University; Gray, Mike (megray@illinois.edu)-University of Illinois; Hammond, Ron (hammond.5@osu.edu)-OARDC/Ohio State University; Hibbard, Bruce (hibbardb@missouri.edu)-University of Missouri; Hughson, Sarah-Illinois Natural History Survey; Kang, JungKoo (kang61@illinois.edu)-University of Illinois; Krupke, Christian (ckrupke@purdue.edu)-Purdue University; McManus, Brad-South Dakota State University; Meinke, Lance (lmeinke@unlnotes.unl.edu)-University of Nebraska; Meyer, Rick (hmeyer@nifa.usda.gov)-USDA NIFA; Miller, Nick-University of Nebraska; Onstad, David (onstad@uiuc.edu)-University of Illinois; Ostlie, Ken (ostli001@umn.edu)-University of Minnesota; Pueppkie, Steve (pueppke@msu.edu)-Michigan State University; Porter, Pat (pporter@ag.tamu.edu)-Texas A&M University; Sappington, Tom (Tom.Sappington@ars.usda.gov)-USDA ARS Ames, IA; Schaafsma, Art (aschaafs@ridgetownc.uoguelph.ca)-University of Guelph, Ontario Canada; Shields, Elson (es28@cornell.edu)-Cornell University; Smith, Jocelyn (jsmith@ridgetownc.uoguelph.ca)-University of Guelph, Ontario Canada; Spencer, Joe (spencer1@illinois.edu) Illinois Natural History Survey; Tinsley, Nick - University of Illinois; Tooker, John (tooker@psu.edu)-Pennsylvania State University; Weber, Patrick-Iowa State University; Wright, Bob (rwright@unlnotes.unl.edu)-University of Nebraska

Brief Summary of Minutes

See Attached Copy of Minutes

Accomplishments

Short-term Outcomes: <br /> <br /> The problem of inability of public-sector scientists to conduct research on commercialized transgenic crops without company permission was not well known before several NCCC46 corn entomologists and colleagues publically warned EPA. In response the American Seed Trade Association (ASTA) drafted a policy statement including principles under which seed companies have committed to allow independent research on their products. The spirit of the new paradigm is being implemented through blanket agreements between seed companies and the public sector (universities and USDA). NCCC46 entomologists continue to lead the initiative and to hold companies accountable to their commitment to abiding by the ASTA principles, as well as to provide guidance to universities for initiating the agreements.<br /> <br /> <br /> Outputs:<br /> <br /> A manuscript was submitted to the Journal of Economic Entomology Commentary Section by NCCC046 authors Onstad et al. titled 'Seeds of Change: Corn Seed Mixtures for Resistance Management and IPM'. The manuscript was accepted and is in press at the time of the January 2011 NCCC046 annual meeting. ABSTRACT: The use of mixtures of transgenic insecticidal seed and non-transgenic seed to provide an in-field refuge for susceptible insects in insect-resistance-management (IRM) plans has been considered for at least two decades. However, the US Environmental Protection Agency has only recently authorized the practice. This commentary explores issues that regulators, industry and other stakeholders should consider as the use of biotechnology increases and seed mixtures are implemented as a major tactic for IRM. We discuss how block refuges and seed mixtures in transgenic insecticidal corn production will influence integrated pest management (IPM) and the evolution of pest resistance. We conclude that seed mixtures will make pest monitoring more difficult and that seed mixtures may make IRM riskier because of larval behavior and greater adoption of insecticidal corn. Conversely, block refuges present a different suite of risks because of adult pest behavior and the lower compliance with IRM rules expected from farmers. It is likely that secondary pests not targeted by the insecticidal corn as well as natural enemies will respond differently to block refuges and seed mixtures.<br /> <br /> Different products from different seed companies now have different refuge requirements. More corn hybrids contain multiple transgenic traits and cost of seed is steadily rising - $300 or more per bag is not uncommon. Meanwhile, refuge requirements are changing for multi-trait corn. Some refuges remain structured at 20% planted in a block or series of alternating rows. Others are reduced to 5% or 10%, either in a block or 'in-the-bag' mixed with the Bt seed. Purchasing the correct transgenic hybrid for the correct target insect pest, and planting it with the correct refuge in the proper location is critical to meeting insect resistance management (IRM) stewardship requirements that come with planting Bt corn. This process can be increasingly confusing for growers and consultants. Michican (C. DiFonzo) and Wisconsin (E. Cullen) co-authored and distributed a two-page Extension fact sheet publication titled 'Handy Bt Trait Table'. This print and online publication is intended for corn growers, crop advisers, agronomists, Extension educators, and related agricultural professionals. Text, insect ID color photographs, and a comprehensive table summarize all corn hybrids X Bt trait combinations currently available for corn rootworms and the above ground lepidopteran pest complex, along with the spectrum of insect control and suppression for each product. The table also lists the refuge percentage and field configuration requirements. Cullen and DiFonzo proofed the publication with US EPA and seed company registrants. Based on feedback, national requests for permission to reprint this publication, and to the best of our knowledge, this Extension publication offers the most complete and condensed version of text, photos, and table reference providing Bt corn IRM information to growers and related clientele.<br />

Publications

Impact Statements

1. Modeling pest resistance to Bt crops demands accurate information on pest movement and other biological parameters. Studies measuring western corn rootworm movement and mating in several configurations of refuge and transgenic corn found that a 5% seed blend yielded uniform WCR abundance and mating across the field. If seed blends are viable and sustainable management tools they will also assure near 100% grower compliance with refuge requirements. (IL: Joe Spencer and Sarah Hughson)
2. In small fields, potential for western corn rootworm egg-laying and injury can be significantly concentrated onto a small percentage of the field by trap cropping. By employing transgenic corn hybrids, on small portions of their farms were the potential for injury has been focused; growers would save production costs and reduce the selection for pest resistance to transgenic hybrids. Trap cropping did not work reliably in large producer-scale fields. (IL: Joe Spencer, Kevin Steffey, Mike Gray).
3. Distinctions between rotation-resistant and susceptible WCR populations in expression of digestive enzymes following soybean herbivory suggest that resistance is, in part, tied to adult gut physiology adaptations. Identifying novel gene expression pathways linked to rotation resistance may at last offer scientists a tool to distinguish resistant and susceptible individuals. (IL: M.J. Seufferheld, J.L. Spencer/J. Zavala, Univ. of Buenos Aires).
4. A study documented frequency of Northern Corn Rootworm extended diapause trait throughout Nebraska. Egg hatch data over two years indicates the trait is present in all populations with significant variation among populations. Highest frequency occurred along north-south transect parallel to the Missouri River. Results add knowledge of diapause and genetic variation for this species and contribute data required for revised management recommendations in different areas of NE. (NE: Lance Meinke).
5. USDA, ARS, NCARL Brookings, SD rears corn rootworm colonies collected from throughout the U.S. Corn Belt. Many colonies have unique characteristics of resistance. Use of these colonies has been instrumental in several recent studies in North America and Europe. USDA prescience to establish and maintain these colonies continues to enable comparative research permitting a greater understanding of pest biology, ecology, genetics, chemical and Bt resistance, ecology, and behavior. (SD: Wade French).
6. Western corn rootworm has recently become established as a pest of maize in the Europe after introductions from North America. Economists have conducted a multi-nation review of the potential economic impacts of the pest in Europe and estimation of a damage function. These efforts have contributed to developing research expertise in Europe and improved farm level management of the pest in Europe and informed the policy response of European nations to this invasive pest. (WI: Paul Mitchell).
7. 3,726 Wisconsin corn growers and agricultural professionals, plus at least 2,400 growers in 5 additional states (MI, IN, ND, MN and VA) gained knowledge of different IRM refuge requirement for different Bt corn hybrids from different seed companies and increased their capacity to respond with improved IRM stewardship compliance based on the Extension fact sheet co-authored by MI and WI titled Handy Bt Trait Table (MI: Chris DiFonzo and WI: Eileen Cullen).

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