Brief Summary of Minutes of Annual Meeting

The 2007 annual meeting of S-1010 was held 11-13 March in Portsmouth, Virginia. Attendees included 28 university and government entomologists from both the U.S. and Canada. On Sunday, 11 March, a subset of participants met with Dr. Scott Isard and Julie Golod from Pennsylvania State University to finalize sampling plans and data input for the soybean aphid PIPE (Pest Information Platform for Extension and Education) web site, sponsored by USDA at http://www.sbrusa.net/. On Monday, 12 March, the chair of the technical committee, Christina DiFonzo, opened the meeting at 8:00 am. Wayne Bailey served as secretary in place of Mo Way and Ames Herbert was responsible for local arrangements. State reporting for the meeting was done electronically; participants received a file on a CD or memory stick with the state reports, slide sets, bulletins, publications and other information. Rick Meyer, USDA CSREES, distributed a handout on USDA CSREES employees and discussed current staffing. A second handout illustrated the budget with discussion on the loss of line item funding and the manner in which funds will be available for this year and future years. He discussed possible changes in the Agency, for example the potential merger of CSREES and ARS. David Boethel, S1010 Administrator, discussed the termination of the existing project and the rewrite of a new project. He also emphasized the need for impact statements for all funds. Due to lack of impact statements in past, there is a move to change from special grants (pass-through $) to competitive grants. Land grant institutions may lose if funds are shifted to competitive grants. In response, land grant institutions developed the Create 21 program of funding for agricultural research. The goal of this program is to keep formula funds as is and put new dollars into the competitive grants. Rick Meyer stated that at least two other funding models are being considered in addition to Create 21. David Wright from the North Central Soybean Research Committee was a guest visitor. He manages the NC Soybean Research Program and the Iowa Soybean Checkoff Board, and works closely with the United Soybean Board. He discussed current soybean research projects in the NC region. At present $2.4 million is being spent on soybean research. A discussion ensued concerning future funding needs and research directed at specific insects and pathogens. Other discussion topics included specialty beans, biodiesel, and cooperative ventures between the NCSRP and state soybean boards. Ames Herbert and Eileen Cullen discussed changes to the PIPE observation form as suggested during the March 11, 2007 meeting. Several concerns were expressed and additional changes to the document suggested. The form will be revised to address concerns suggested by the S1010/PIPE participants. At the end of the morning session, Chris DiFonzo initiated a detailed discussion on the Statement of Issues and Justification for a new project. A writing committee met in December 2006 to develop new objectives. During the meeting, these objectives and sub-objectives were reviewed and rewritten, and participants identified to lead the writing of that section. The remainder of Day 1 and the morning of Day 2 were spent on reports by objective. On Monday evening, participants toured the Perdue Farms port facility in Chesapeake, VA, one of the few bulk grain handling facilities left on the east coast. The meeting adjourned at noon on 13 March 2007. The location for the 2008 meeting is tentatively Savannah GA, hosted by Bob McPherson, in mid-March. Mo Way is the incoming S-1010 Chair and Matt ONeal the incoming secretary, for 2008.

Outputs and Activities from the last year: Objective 1a. Develop management strategies for the soybean aphid. Surveys Many states participated in a field survey coordinated by Purdue University. Fields were sampled weekly for aphid number and plant stage. In many cases the information was placed on the USDA PIPE web site to generate an aphid map during the field season. In Virginia, an extensive state-wide soybean aphid survey monitored 50 fields across soybean growing regions from mid June through early October. Counts were entered into a database and summaries were provided to growers, agents, and crop advisers on a weekly basis. Although soybean aphid infested many fields in Virginia, this field monitoring effort detected only one location at risk to crop loss. This information passed to clientele on a timely basis resulted in a limited use of insecticide. The NC aphid suction trap network operated in 10 states in 2006. Few aphids were collected in July and August moving from soybean to soybean. However, the numbers increased in the fall in many states. Soybean aphid oviparae and eggs were observed on buckthorn in several states. The largest numbers of eggs were observed in samples taken near the Quad Cities. Soybean aphid eggs were found on every randomly collected twig, and most twigs had eggs near with every bud. Based on the trapping and field observations, 2007 is predicted to have greater aphid populations. Biology Researchers in Ontario investigated potential olfactory cues for parasitoids produced by the interaction of the soybean aphid with its plant hosts. Three species of Aphidius parasitoids were evaluated in two-choice olfactometer bioassays for their response to volatiles from the primary host, Rhamnus cathartica, undamaged or infested and fed on by SBA. A. colemani responded to both aphid-damaged and undamaged R. cathartica. Preliminary data from growth chamber and field micro-plot experiments at Iowa State indicates that soybean cyst nematode infection and SBA infestation interact. SBA population growth and subsequent abundance did not vary with SCN presence, but plants were smaller when infected with SCN. Thus, the density of aphids per unit of plant tissue was significantly greater on SCN infected soybeans. The combination of SCN and SBA reduced soybean height and seed weight more than when plants were infested by either pest alone. A study in Nebraska examined impact of irrigation, planting date, and maturity on SBA. Aphid populations were greater on non-irrigated (water-stressed) than irrigated soybeans. Initial aphid numbers also were greater on non-irrigated plants, implying an increase in susceptibility or attractiveness to the aphids. In irrigated plots, more aphid-days were accumulated on 2.7 than 3.0 maturity group beans. In non-irrigated (stressed) plots, aphid-days and aphid numbers were higher on the 2.7 maturity group beans. SBA had a significant effect on yield; a decrease in seed weight was observed with higher aphid numbers in both irrigated and non-irrigated treatments. However, the aphid x water interaction showed no significant effect. Gas exchange measurements (photosynthesis, stomatal conductance, and transpiration) were performed on three dates. In general, gas exchange parameters were higher in irrigated and early-planted soybeans. No aphid related effects were observed until mid August. At this time various effects and interactions were observed, although trends were not apparent, indicating that aphid densities of higher than 12 aphids/leaflet and/or a greater moisture stress are required to significantly impact soybean physiology. Insecticides Most states across the region experienced very low aphid numbers in 2006. Under no or low aphid pressure, replicated plots in most states did not show a significant yield increase from the use of seed treatments compared to untreated plots. In Illinois, 26 insecticides and insecticide tank mixes were evaluated by measuring aphid density after treatment and taking plot yields. Densities varied considerably among the plots and were generally relatively low, but densities of aphids in most single-insecticide treatments were statistically lower than densities of aphids in the untreated check for the duration of the experiment. On all sampling dates, most foliar applied treatments had comparable performance to the most effective treatment with the fewest aphids per plant. However, the yields of all treatments were not significantly different from the yield in the untreated check. In Iowa, where both bean leaf beetle and SBA are pests, insecticide programs to control early-season BLB were tested for their impact on SBA. There was no significant overlap of the overwintering or first generation populations of BLB with SBA, which occurred later in the season. In a three-year study, insecticides targeting overwintering or first generation BLB did not prevent or reduce economic populations of SBA. Furthermore, the highest SBA populations were observed when insecticide targeted the overwintering BLB population. These results suggest that the use of foliar insecticides early in the season for BLB management may lead to resurgence of aphids later in the season. In Nebraska, bioassay techniques were developed to determine baseline susceptibility of SBA to neo-nicotinoids. Imidacloprid and thiamethoxam produced similar responses and were very toxic to SBA with low LC50s. There were also significant sub-lethal effects at even lower doses. Thresholds In South Dakota, three yield loss experiments to test a series of soybean SBA thresholds. Aphid densities at two sites permitted tests up to c. 800 aphids per plant. There was no significant yield loss among any threshold treatments. The Tilmon lab will advocate the 250 threshold for South Dakota and work to educate the extension program about the scientific validity of this threshold and its benefit to producers. Minnesota (Ragsdale lab) is working on a method to estimate aphid population densities by counting specific nodes. Node counts would be useful in management and research situations where aphid-density is high and whole-plant counts become too labor intensive or time consuming. Based on comparing whole plant counts to counts at individual nodes, they suggest taking a two-node sample when plants are small (5 nodes or fewer) and increasing to a four-node count when plants are taller. Host Plant Resistance Many states evaluated germplasm for SBA resistance in the greenhouse, field cages, or open plots. South Dakota and Minnesota had higher aphid numbers than other states, and they were able to detect significant differences in number of aphids per plant among lines. In Kansas, 11 entries exhibited partial levels of antibiosis; some lines shared the Rag1 gene, while others may be novel forms of resistance. Polymorphic SSR markers are being used to genotype Kansas lines. Based on electrical penetration readings, SBA feeding was different between the susceptible check and the resistant entries. Aphids took longer to reach, and spent less time in, the sieve elements in the resistant entries. This suggests that morphological or chemical factors in the phloem tissue of resistant plants affects stylet penetration activities of SBA. The most resistant entry, K1639, has both SBA and SCN resistance and will be released in 2007 Objective 1b. Validate emerging management strategies for the bean leaf beetle The USDA-ARS lab in Brookings, SD is perfecting the rearing of BLB, with the long term goal of developing a mass production system. The process is extremely time-intensive and involves breaking adult diapause, collecting eggs laid by females, and transferring individual larvae several times before pupation. The generation time in culture is approximately 30 days from egg to adult. Issues that remain include optimizing egg collection, exploring less labor-intensive larval production methods, and determining cues used by laboratory-produced adults to initiate oviposition. In the greenhouse, the USDA-ARS lab studied the impact of larval feeding damage on nitrogen (N) assimilation and root system characteristics in soybean. Individual potted plants were exposed to varying numbers of larvae. After 3 weeks, plants were sacrificed and data were collected on the fresh and dry weights of the roots and shoots, numbers of nodules and damaged nodules, nodule volume, and N concentrations. Nodules were the only organs on the root system that were visibly damaged by larval feeding. Nodules on infested plants were more numerous and smaller, suggesting that the infested plants respond to larval damage by producing additional nodules. Leaf and pod ureide-N and total N concentrations from infested plants were significantly lower in infested plants. Thus, feeding by C. trifurcata larvae affects the characteristics of nodules as well as the concentrations of N assimilates within soybean plants. Objective 1c. Management strategies for insect and other arthropod pests of soybean under multiple and/or combined stresses, value-added soybeans, and transgenic soybeans. Stink bugs remained an area of active research in 2006. Five stink bug pest species were found in Virginia crop fields, three of which were previously unknown. Five species of parasitic wasps were attacking and killing stink bug eggs. Rates of egg parasitism were high for the two main stink bug species, with 49% of all brown, and 47% of all green, stink bug eggs being killed. Work continues with egg parasites to determine if they can be manipulated to our advantage. In Texas, data showed soybean fields must be scouted carefully and often, particularly red-banded stink bug (RBSB), which has become the most serious pest of early-maturing soybeans in SE Texas. Between R3 to maturity, soybeans can be severely damaged by RBSB. Data show that currently labeled insecticides provide adequate control of RBSB, but these insecticides may have to be applied more than once. In Georgia, heavy pod damage in the mid-R5 stage causes green bean syndrome in soybeans, thus it is important that populations during this time are effectively controlled to prevent severe yield losses. Studies on green bean syndrome were initiated in 2006. To simulate severe stinkbug injury to soybeans, all pods on all plants in a single row were removed at the R3-R4, early R5, late R5, or mid-R6 growth stages. Growth stages, senescence qualities, and yield were compared in depodded and control plots. At harvest, plots depodded in the late R5 and R6 stages were still green. Plots depodded at late R5 had a proliferation of blooms and small, deformed pods. Plots depodded at R6 no pods, just green barren plants. Yields among the various treatments were significantly different. These results suggest that heavy pod damage during or after the mid-R5 plant stage could, at least in part, be the cause for green bean syndrome in soybeans. In Mississippi, stink bug threshold research on R7 stage beans continued. In 2006, both yields and quality suffered from R7 infestations with southern green stink bug. From two years of large field cage research it appears that the economic threshold for stink bugs in R7 stage beans is between 1 and 2 stink bugs per row foot on a drop cloth. Edamame research: Research on vegetable soybean (edamame) in southern Georgia concluded that this commodity can be efficiently produced utilizing most of the current soybean culture methods. The early-maturing variety, Midori Giant, can be harvested 60 days after planting. This variety, when planted from mid- April to mid-May, escapes most of the insect-induced crop injury caused by stink bugs and caterpillars. However, yields are lower compared to conventionally produced beans. Later-maturing edamame varieties have economically damaging infestations of soybean insect pests, but these pests can be effectively managed through the judicious use of insecticides. When left untreated, over 50% of the soybean kernels had stink bug damage in the later maturing varieties, while the Midori Giant had only 10-20% damaged kernels in the untreated plots. Later-maturing varieties matured several weeks later than the early varieties and stink bugs migrated to them as the other entries senesced. Yields attained in these field trials indicate that edamame can be efficiently produced in Southern Georgia. Host Plant Resistance: As an alternative to insecticides, soybean varieties and breeding lines were screened in Georgia for stink bug and lepidopteran resistance; some entries showed reduced seed damage or defoliation. The entries expressing stink bug and lepidopteran resistance will continue to be examined for resistance. Studies to examine the mechanisms of resistance (antibiosis and non-preference) have been initiated under laboratory and field choice and no-choice feeding conditions. Dectes stem borer: A survey for Dectes stem borer found that this insect reached pest status even in eastern states. There were reports of serious stem borer infestations in MO, KY and DE in 2006. In Kansas, field cages work better than greenhouse trials to assess germplasm for stem borer resistance. Two PIs screened in the trials show promise; they had many oviposition punctures, but few surviving larvae. Yield response of soybean varieties to stem borer feeding, with and without insecticide application, was assessed in several locations in Kansas. Yield in treated and untreated plots was similar despite the presence of stem borer damage. Therefore, the study did not show a yield response to stem borer infestation. Objective 2: Define insect-vector ecology and virus-disease relationships and develop management strategies. Chemical: Studies in Wisconsin confirmed that a single application of an insecticide does not suppress transmission of non-persistent viruses transmitted by SBA. Host plant resistance: Field experiments in Wisconsin determined the relative reaction of commercial soybean cultivars to soybean viruses. None of the commercial cultivars expressed complete resistance to soybean mosaic, but several expressed a tolerance based on lower incidence of symptoms, infection, and mottled seed-coat, and yield comparable to resistant check cultivars. A variety resistant to alfalfa mosaic was identified; the resistance is inherited as a single dominant gene. However, isolates of alfalfa mosaic were found that overcame the virus resistance. Work continues to merge SBA resistance with resistance to plant pathogens and soybean cyst nematode. Soybean accessions with resistance to the SBA were verified in greenhouse trials. The resistance was derived from Jackson and Dowling (Rag1 gene) and a previously unreported source of soybean aphid resistance. Resistance derived from this new source is inherited as a single dominant gene based on the segregation pattern of F2 populations. F3 progeny will be evaluated to confirm phenotypic data derived from the F2 population Ecology: Aphid-transmitted viruses have contributed to recent disease epidemics in commercial beans. In Wisconsin, the seasonal progression of aphid flight activity patterns was characterized in different plant habitats, to determine the importance of SBA as a virus vector. Water pan traps were placed in different habitats across Wisconsin to monitor SBA alate abundance from May to September. Leaf samples were taken from symptomatic plants in each habitat and assayed for virus using ELISA. Habitats included snap beans, clover, field edges, and commercial fields of alfalfa, carrot, pea, and soybean. Alate abundance peaked twice during the growing season, in early July and especially in early August. SBA appeared in traps by late June. Numbers were low until early August, when SBA constituted 86% of the total alates captured in all habitats. Assays confirmed the presence of many non-persistently transmitted viruses. Objective 3: Biological control of soybean aphid in North America Objective 3a: Importation of exotic parasitoids for controlling soybean aphid Exploration continues for soybean aphid natural enemies in Asia. Dr. Kim Hoelmer, USDA/ARS quarantine lab, visited China from 19 June - 15 July 2007 to survey early summer parasitoids of SBA in several regions of China. Field collections in NE China coincided with travel by Robert ONeil (Purdue) and David Voegtlin (Illinois Natural History Survey) who were in China to work on non-target research with Chinese cooperators. Field collections of aphid mummies were made in several locations. In Beijing, K. Hoelmer met with Drs. Qiao, ONeil and Voegtlin to plan ongoing research and to visit Beijing University, where a diversity of buckthorn species was planted and surveyed for A. glycines and other aphids. Overall, several thousand SBA mummies were collected and returned to the USDA ARS quarantine facility in Delaware. Chinese cooperators also made and sent follow-up collection later in the summer. The USDA/ARS quarantine lab is maintaining populations of parasitoids from several areas in China, Korea, and Japan. Host specificity testing is continuing on some populations, and was completed for others. Several populations were found to have relatively narrow host ranges and releases of these species will be pursued. Several states are preparing for this release by conducting baseline surveys of native aphid species, determining their number and native biocontrol agents. This will help assess the impact of the importation release on native aphids and natural enemies. Objective 3b: Conserving natural predators and pathogens. Conservation biocontrol: In Ontario, a two-year study using aphid-infested field cages provided insight into the impact and response time of several predators of SBA. Multicolored Asian ladybird beetle (MALB) was the most effective of the predators tested. In cages, there was a buildup phase of several weeks in which MALB populations increased to a threshold, after which they dramatically reduced aphid populations and suppressed aphids for the remainder of the cycle. Yields (bean weight) were significantly higher in cages where MALB was present than in cages lacking MALB. In Iowa, the effect of reduced risk (systemic or selective) insecticides was assessed on SBA populations and aphid natural enemies. Warrior, a conventional insecticide, had a significant negative impact on the total number of natural enemies. However, systemic seed treatments and selective insecticides had no observable effect on natural enemies. Extension: S-1010 members contributed to the biological control web site hosted by Univ of Wisconsin (http://www.entomology.wisc.edu/sabc) and the soybean aphid biocontrol e-conference (March, 6, 2007) at 170 remote locations.

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