Brief Summary of Minutes of Annual Meeting

Joan Campbell, chair, called the meeting to order at 3:45 pm. Attendance sheet was passed and attendees introduced themselves. Michael Harrington, executive director of Western Association of Agricultural Experiment Station Directors, attending by phone, gave a Multistate Committee Update and a presentation on the new farm bill.

The seeding direction study was the first item of discussion. Andrew Kniss has combined data from all sites and looked for patterns in seeding direction impacts on downy brome. Site latitude was considered as a co-variate in the models. No obvious patterns of significance were noted; however this may be from the lack of replication (n=4) and the abnormal drought conditions at several sites that may have limited downy brome emergence.

The second item of discussion was on feral rye. Seed was collected from four sites in 2015 and additional three sites in 2016. The seed has not yet been consolidated for use in common gardens. A bew protocol for seed collection will be established for 2017. For every field to be sampled, 5 heads will be collected from 5 plants distributed throughout a field. (Nevin Lawrence will write a protocol and send it to the group.) Seeds will be sent to a single site (TBD), and seed increased at that site to minimize maternal effects. After seed increase, a common garden experiment will be conducted at various sites throughout the range of feral rye representing eco-climatic areas from north to south and east to west. The details of the common gardens are to be determined by a sub-committee of Joan Campbell and Ian Burke. Seed not included in the common garden will be included in genotyping.

The third item of discussion was potential grant proposals. There is a possibility that funding for the feral rye study including understanding feral rye herbicide resistance can come from the Western IPM center. The NIFA CPPM program was also mentioned as a possibility. Andy Hulting will obtain more information and further investigate these possibilities.

Judit Barroso was elected secretary/chair elect. Erik Lehnhoff will serve as chair. The next meeting will be held March 12, 2018, 3:00-5:00 PM before the Western Society of Weed Science meeting in Garden Grove, CA. Meeting adjourned at 5:00 PM.

IDAHO REPORT

Joan Campbell, Research and Instructional Associate; Traci Rauch, Senior Research Specialist; and Don Morishita, Extension Weed Scientist.

PSES Dept, University of Idaho, 875 Perimeter Dr. MS 2339, Moscow, ID 83844; 208-885-7730; jcampbel@uidaho.edu

Objective 1. Results: Winter wheat tolerance was evaluated in Zidua formulations with and without irrigation, different rates and timings. A new liquid formulation decreased yield with same day irrigation compared to no irrigation. The same formulation in a non-irrigated study decreased yield at a high vs. low rate at a per-germination timing. No yield difference between rates if wheat was germinated. The second year of Anthem Flex winter wheat variety tolerance trial indicated some injury to Brundage96, but not Boundary, Cara, or Silver. In winter wheat, Italian ryegrass control with Anthem Flex was best with the highest rate at the postplant pre-germinated wheat timing. It was better than the preplant timing most likely due to the shorter time period for activation by rainfall (30 days preplant vs. 11 days postplant). Italian ryegrass control in spring wheat with Anthem Flex showed rate dependent Italian ryegrass control at the preplant timing vs. the germinated wheat timing. Anthem Flex rate and timing evaluations will be continuing in winter and spring wheat. A winter wheat/Italian ryegrass control study evaluated Zidua and Anthem Flex at the highest labeled rates with the following application times:  pre-fertilization (shanked deep band liquid application equipment), post fertilization, postplant no germination and postplant germinated wheat. Italian ryegrass control with both herbicides was improved with less disturbance. The two postplant applications times differed due to time of activation with rainfall. Rain fell 18 days after the non-germinated application versus 3 days after the germinated wheat application. This study is being repeated in 2017. In 3 studies, rattail fescue was controlled 88% or greater with Zidua and Anthem Flex applied postplant preemergence in the fall alone or in combination with spring postemergence applications. Spring applied Everest, PowerFlex, and Maverick only suppressed rattail fescue. These studies will be repeated in 2017. Downy brome was controlled 80% or greater with Zidua, Anthem Flex and PowerFlex HL.

Objective 2. Results: A field trial was established at UI research farms near Moscow and Genesee to examine tillage effects on rattail fescue. Winter wheat was direct-seeded in fall 2013. The rotation is winter wheat- spring wheat- spring chickpea. Tillage initiated in the fall 2014 included fall disc or chisel plow followed by spring field cultivation. A no-tillage treatment is included as a control. Heavy harrow will replace disc in year 2 and 3. The tillage is performed all 3 years, 2 years or 1 year for a total of 7 tillage regimes. Spring chickpea was seeded in 2016. Rattail fescue populations were low in the chickpea year of the tillage comparison study. The weed was found only in no-till and the one year of chisel plow. Tillage treatments were applied and winter wheat has been planted this fall for the third year of the study.

Objective 3 Results. Two new broadleaf weed control herbicides in winter wheat were evaluated. Talinor (bicyclopyrone/bromoxynil) controlled a heavy mayweed chamomile population 98-99% which was better than Huskie and Starane Flex. Winter wheat yield was greater in the Talinor treatments compared to Widematch. Tarzec (halauxifen/pyroxsulam) controlled catchweed bedstraw 90-98% but did not control mayweed chamomile. A new postemergence grass herbicide, Osprey Xtra (mesosulfuron/thiencarbazone), controlled rattail fescue better than Everest and Osprey. Studies this spring will continue to evaluate these new herbicides for weed control efficacy.  A new stripe rust fungicide (3 active ingredients) was evaluated in combination with different herbicides. The fungicide (at two different rates) combined with PowerFlex, Widematch and MCPA ester reduced yield compared to the check. Another study will be conducted in 2017.

Objective 4 Results. Suspected-resistant weed seed samples collected from research plots and submitted by growers, fieldmen, and industry representatives were screened in the greenhouse. The weed seed samples were grown in the greenhouse and sprayed with suspected-resistant and non-resistant herbicides at twice the labeled rate. Susceptible plants were included to verify herbicide spray coverage and rate. Seeds were counted at planting with preemergence herbicides and plants are counted at emergence with postemergence herbicides. Untreated plants were included from each sample. Resistance was evaluated on plant survival and vigor compared to the untreated. In 2015, nine Italian ryegrass seed samples were treated with 12 different herbicides. No sample screened was resistant to Zidua, Dual Magnum, or glyphosate. Samples were resistant to Amber, Everest, Osprey, and PowerFlex (group 2) and Poast, Assure II, Shadow (clethodim) and Axial XL (group 1) and Axiom (group 15 and 5). Four wild oat seed samples were treated with 8 herbicides. No sample was resistant to Shadow, Poast, Beyond, Axial XL, and glyphosate. Samples were resistant to PowerFlex, Osprey (group 2), and Assure II (group 1).

Objective 5 Results: Project personnel participated in cereal school meetings in north Idaho in January. Research information was presented at the Western Society of Weed Science regional meeting in March. Wheat system information was presented at International Weed Science Congress in June. Cereal research was also presented at field days in north and south Idaho in June and July.

KANSAS REPORT

Kochia has been an economically important broadleaf weed in the US Great Plains including Kansas. However, in the recent years, Palmer amaranth has also become a major problem weed in Kansas. Specifically, evolution of multiple herbicide resistance in kochia and Palmer amaranth, is a serious threat to sustainable crop production. We have confirmed resistance to four modes of action of herbicides in a single kochia population from a crop field near Garden City, and this was reported in last year’s progress report. Additionally, environmental factors such as temperature shown to have significant effect in managing kochia populations with dicamba and glyphosate, commonly used herbicides for kochia management. We recently confirmed resistance to modes of action of herbicides in Palmer amaranth in several Counties in KS.

Effect of Growth Temperature on Dicamba and Glyphosate Efficacy in Kochia.

Kochia (Kochia Scoparia) is a major problematic weed in United States and Canada. Dicamba and Glyphosate offer effective herbicide options to control kochia. Previous research showed the efficacy of dicamba and glyphosate varied under different environmental conditions, including plant growth temperature. In this study, the effect of growth temperature on efficacy of dicamba and glyphosate in kochia was investigated. Dicamba- and glyphosate- susceptible kochia plants were grown in growth chambers maintained at different temperatures (day/night, °C): low (LT), 17.5/7.5; optimum (OT), 25.0/15.0; and high (HT), 32.5/22.5. When plants reached 8-10 cm tall, they were treated with 0, 1/32, 1/16, 1/8, 1/4, 1/2, 1X rates of dicamba (where X is 560 g·ae·ha-1) or glyphosate (where X is 840 g·ae·ha-1). Visual injury, fresh and dry biomass were recorded 4 weeks after treatment (WAT). Each treatment had 4-6 replications and experiments were done twice. Furthermore, dicamba and glyphosate uptake and translocation experiments were conducted using 6-8 cm tall kochia plants grown under above temperatures. Ten μL of dicamba (3.0 g·ae·L-1) or glyphosate (4.5 g·ae·L-1) containing 20,000 dpm·μL-1 14C radioactivity was applied on two newly matured leaves. At 24, 48 and 72 hours after treatment, the treated leaves (TL) were washed with 20% (v/v) ethanol solution with 0.5% (v/v) Tween-20. Subsequently, the TL, plant tissue above treated leaf (ATL) and below treated leaf (BTL) were harvested, dried and combusted to determine the amount of radioactivity. Results of dicamba dose-response on kochia show the ED50 of xxx, 50.2, 141.9 g·ae·ha-1, at LT, OT and HT, respectively. Whereas, for glyphosate, the ED50 at LT, OT and HT were yy.y, 60.4, and 173.5 g·ae·ha-1, respectively. Analysis of data of uptake and translocation studies indicate that the dicamba is more effective on kochia grown under LT, possibly because of increased translocation compared to plants grown under OT or HT. Similarly, glyphosate was also found more effective on kochia grown under LT than OT or HT. On the contrary, this increased efficacy of glyphosate under LT may be attributed to increased uptake of the herbicide rather than the translocation.

NEW MEXICO REPORT

Erik Lehnhoff and Abdel Mesbah, New Mexico State University, Department of Entomology, Plant Pathology, and Weed Science

In New Mexico, one study on tank mixing Huskie with broadleaf herbicides for weed management in winter wheat is being conducted in Clovis. Results show improved control of broadleaf weeds including kochia, Russian thistle and pigweed. It is too early in this study to present impacts.

WASHINGTON REPORT

Drew J. Lyon and Ian C. Burke

Research:

Mayweed chamomile control in winter wheat with Talinor. A field study was conducted at the WSU Palouse Conservation Field Station near Pullman, WA to generate broadleaf weed control data with Syngenta’s Talinor herbicide in winter wheat. Talinor is a premixture of bromoxynil (Group 6) and bicyclopyrone (Group 27) herbicides. Talinor is tank mixed with CoAct+™, which is a safener. Huskie® contains pyrasulfotole, which is also a Group 27 herbicide, and bromoxynil, and is why it is used as a comparison treatment against this new active ingredient combination. Talinor alone, Talinor plus the tank mix partners tested, and Huskie alone provided greater control of mayweed chamomile 15 days after application than the Affinity Tankmix and WideMatch treatments. On June 17th, 57 DAT, Talinor treatments exhibited better control of mayweed chamomile than the Huskie treatments. The exception was Talinor + CoAct+ + Axial Star, which provided similar mayweed chamomile control to Huskie at 15 fl oz/A. There did not appear to be a rate response for Talinor treatments like there were with the Huskie treatments. When the final rating was taken on July 5th, 75 DAT, all treatments were providing good to excellent control of mayweed chamomile except Huskie at 11 fl oz/A. Talinor is an effective herbicide for mayweed chamomile control in winter wheat.

Rush skeletonweed control in winter wheat following CRP takeout. Rush skeletonweed is a deep-rooted perennial species that has become well established on thousands of acres across eastern Washington while the land was out of wheat production in the Conservation Reserve Program (CRP). Recent changes to the CRP have resulted in many acres coming back into production and most often without prior skeletonweed control. Uncontrolled skeletonweed in the fallow phase of the rotation reduces seed-zone moisture and leaves inadequate soil moisture for germination of winter wheat in the fall. Areas where wheat fails to emerge are either late-seeded after fall rains replenish soil moisture or are left blank. In either case, crop yield is reduced. Herbicide control in the crop phase is one part of an overall strategy to reduce or eradicate skeletonweed from these production areas. We applied five different synthetic auxin herbicides to rush skeletonweed infested winter wheat on November 12, 2015 as the wheat was tillering and again prior to stem jointing on March 17, 2016, at a field site near LaCrosse, WA. In this trial, fall applications of Milestone or Stinger substantially controlled rush skeletonweed in the crop phase of the rotation without reducing grain yield. The experimental DPX-MAT28-128 and 2,4-D LV6 did not control skeletonweed well and appeared to reduce yield. Clarity did not lower yield, but also did not control skeletonweed.

Downy brome vernalization and dormancy. Downy brome is arguably one of the worst invasive weed species in both natural and agronomic environments in the United States. Phenological variation is a key factor in the success of the species as a competitor in wheat production regions of the inland Pacific Northwest (PNW). Prior research characterized vernalization and flowering time requirements of downy brome collected from different environments, but no previous work has focused on the connection between such phenotypic responses with the genotypic control of vernalization. A series of common garden experiments was conducted involving 85 accessions of downy brome collected from within small grain production fields of Washington, Oregon, and Idaho. Results of previous common garden experiments identified differences in time to flowering of up to 19 days and time required for mature seed production of up to 21 days among accessions with little variation among siblings. From the common garden experiments cumulative growing degree days required for mature seed production for each accession was estimated using non-linear regression. A series of greenhouse experiments was conducted to characterize the vernalization requirements of downy brome accessions demonstrating differences in development and flowering time, and to determine if differences in expression of VRN1 orthologues is associated with differences in flowering time. Semiquantitative PCR was used to measure VRN1 expression in eight downy brome accessions with different vernalization requirements. Expression of a VRN1 orthologue was only observed in treatments were flowering occurred, suggesting that the molecular controls regulating vernalization and flowering in downy brome are likely conserved with those in related species.

To address seed dormancy, research was conducted to explore the central hypotheses that differences in seed dormancy contribute to extensive phenotypic plasticity and adaptability in downy brome in small grain agricultural settings, and dormancy differences are regulated by changes in sensitivity to and signaling of the two plant hormones abscisic acid (ABA; dormancy promoting) and gibberellin (GA; germination stimulating). Phenotypic differences in seed dormancy were measured at physiological maturity utilizing a core collection of downy brome accessions from six population clusters across the dryland cropping areas in PNW (Lawrence and Burke). Seed dormancy and dormancy release were measured through changes in sensitivity to ABA and GA across an after-ripening time course, and in response to dark or light. Our preliminary findings suggest that: 1) at physiological maturity all accessions screened fall into the "dormant" category (0-25% germination) regardless of population cluster, 2) dormancy release occurs as a result of measurable changes in sensitivity to ABA and GA, as well as other environmental cues such as light, and 3) there are at least 4 distinct dormancy scenarios that exist among downy brome accessions which may not be associated with population cluster.

Herbicide resistance screening of downy brome. We have established a herbicide resistance screening program. To date, initial screens for 34 individual biotypes from a total of 13 locations across the states of Washington and Oregon have been completed. With the implementation of new methods including the addition of a gibberellin (GA) treatment to break seed dormancy, and the use of high through-put screening, we are able to rapidly and reliably identify herbicide sensitivity, tolerance, and resistance. From the initial screens, 7 biotypes were identified with no resistance, 9 with resistance to Beyond, 4 with resistance to Osprey, 5 with resistance to Olympus, and 2 with resistance to PowerFlex. Additionally, tolerance was discovered in 4 biotypes treated with Beyond and 2 treated with Olympus. None of the biotypes screened demonstrated resistance to glyphosate or Select Max. Degree of resistance is currently being tested in biotypes identifies from original screens.

Peer Reviewed Publications

Nakka S, Godar AS, Wani PS, Thompson CR, Peterson DE, Roelofs J and Jugulam M. 2017. Physiological and molecular characterization of hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitor resistant Palmer amaranth (Amaranthus palmeri S.Wats.). Front. Plant Sci. | doi: 10.3389/fpls.2017.00555 (KAES # 16-345-J).

Varanasi VK, Bayromov S, Prasad PVV and Jugulam M. 2017. Expression profiles of psbA, ALS, EPSPS and other chloroplastic genes in response to PSII-, ALS-, and EPSPS-Inhibitor treatments in Kochia scoparia. American J of Plant Sci. 8:451-470 (KAES # 16-370-J).

Ou J, P.W. Stahlman and Jugulam M. 2016: Reduced Absorption of Glyphosate and Decreased Translocation of Dicamba Contribute to Poor Control of Kochia (Kochia scoparia) at High Temperature. Pest Manag. Sci. DOI 10.1002/ps.4463. (KAES # 16-267-J). (IF 2.9)

Jugulam M and Dillon AJ. 2016. Genomic Distribution of EPSPS copies conferring glyphosate resistance in Palmer amaranth and kochia. Indian J of Weed Sci. (KAES # 17-237-J). 48: 132-135.

Tautges, N. E., T. S. Sullivan, C. L. Reardon, and I. C. Burke. 2016. Soil microbial diversity and activity linked to crop yield and quality in a dryland organic wheat production system. Appl. Soil Ecol. 108: 258-268.

Tautges, N, Borrelli, E. P. Fuerst, and I. C. Burke. 2016. Competitive ability of rotational crops with weeds in dryland organic wheat production systems. Renew. Ag Food Sys. (doi: 10.1017/S1742170516000028).

Young, F. L., D. K. Whaley, N. C. Lawrence, and I. C. Burke. 2016. Feral rye (Secale cereal) control in winter canola in the Pacific Northwest. Weed Technol. 30: 163-170.

Kerbs, B. D., A.G. Hulting, and D. Lyon. 2017. Biology and management of scouringrush in dryland winter wheat.  Proc. West. Soc. Weed Sci. Vol.70: (In Press).

Bobadilla, L. K., A.G. Hulting and C.A. Mallory-Smith. 2017.  Management of multiple resistant Italian ryegrass-characterizing resistant populations. Proc. West. Soc. Weed Sci. Vol.70: (In Press).

Liu, M, B. D. Kerbs, A.G. Hulting and C. Mallory-Smith. 2016. Chracterization of multiple herbicide resistant Italian ruegrass (Lolium perenne ssp. multiflorum) populations from winter wheat field in Oregon. Proc. West. Soc. Weed Sci. Vol.69: (In Press).

Roerig, K. C., B. J. Hinds-Cook, A.G. Hulting and C.A. Mallory-Smith. 2016.  Sensitivity of ‘Bobtail’ winter wheat to flufenacet-metribuzin. Proc. West. Soc. Weed Sci. Vol.69: (In Press).

Roerig K. C., D. W. Curtis, A.G. Hulting, and C.A. Mallory-Smith. 2017.  ‘Bobtail’ winter wheat sensitivity to flufenacet/metribuzin by seeding rate and herbicide application rate.  2017 Western Society of Weed Science Research Progress Report. ISSN-0090-8142. 1pp.

Roerig K. C., D. W. Curtis, A.G. Hulting, and C.A. Mallory-Smith. 2016.  Effect of planting date and application timing of flufenacet-metribuzon and pyroxasulfone on ‘Bobtail’ winter wheat yield and Italian ryegrass control.  2016 Western Society of Weed Science Research Progress Report. ISSN-0090-8142. 2pp.

Ingegneri, L.M., M.P.Quinn, A.G. Hulting and C.A. Mallory-Smith. 2015. A short growing season negatively affects progeny vigor in jointed goatgrass (Aegilops cylindrical). Agricultural Sciences 6:315-324.

Conference Presentations

Ou J, Stahlman PW, Fritz AK and Jugulam M. Dicamba- and glyphosate-resistant genes are not linked in kochia (Kochia scoparia). Weed Science Society of America, Annual Meetings, Tucson, AZ (abstract 150).

Menzer S, Jugulam M and Thompson CR. Temperature effect on efficacy of POST-herbicides to control Palmer amaranth (Amaranthus palmeri) in grain sorghum. North Central Weed Science Society, Annual Meeting, Des Moines (abstract 131).

Ou J, Thompson CR, Stahlman PW, Jugulam M. 2016. Efficacy of Glyphosate and Dicamba Tank-Mixes in Kochia. Western Society of Weed Science, Annual Meeting, Albuquerque, NM (abstract 135).

Betha S, Thompson CR, Peterson DE, Jugulam M. 2016. Increased HPPD gene and protein expression contribute significantly to mesotrione resistance in palmer amaranth (Amaranthus palmeri). Weed Science Society of America, Annual Meeting, San Juan, PR (abstract 222).

Bramhall JA, Varanasi A, Dille JA, Jugulam M. 2016. Impact of Crop Competition on Fitness of Glyphosate-Resistant Kochia (Kochia scoparia L. Schrad). Western Society of Weed Science, Annual Meeting, Albuquerque, NM (abstract 1).

Ou J and Mithila J. 2015. Effect of elevated temperature on glyphosate and dicamba efficacy in broadleaf weeds. 25th Asia-Pacific Weed Science Society Conference, Hyderabad, India.

Ou J and Jugulam M. 2015. Effect of Growth and Temperature on Dicamba and Glyphosate Efficacy in Kochia. Western Society of Weed Science, Portland, OR (abstract 30).

Extension Publications:

Lyon, D.J., I.C. Burke, A.G. Hulting, and J.M. Campbell. 2017. Integrated management of mayweed chamomile in wheat and pulse crop production systems. Washington State University. PNW 695.

Extension Presentations:

The biology and control of Russian-thistle was presented at seven pesticide recertification events held throughout eastern Washington. The topic was also presented at several other winter meetings held in the region. Herbicide resistance was the other major topic presented during the 2016-2017 winter meeting season.

Extension Decision Support Tools:

Herbicide Mechanisms of Action (MOA) Tool @ https://herbicidemoa.cahnrs.wsu.edu.

Winter Wheat Herbicide Efficacy Tables @ https://herbicideefficacy.cahnrs.wsu.edu.