Specialty crop and minor-use pesticide prioritization at the 2022 IR-4 Food Use Workshop
Participants at the 2022 IR-4 Food Use Workshop identified the most important research projects for the 2023 IR-4 food-use research program.
The IR-4 Project (Interregional Research Project No.4) has been facilitating registration of sustainable pest management technology for specialty crops and minor uses. Since 1963, the IR-4 Project has been the major resource for supplying pest management tools for specialty crop growers by developing research data to support new EPA tolerances and labeled product uses. Specialty crop research needs are prioritized each year during a national workshop since resources are limited (quoted from the IR-4 Web).
Research priority A’s for the year 2022 field program for fruits, vegetables, nuts, field and oil crops, herbs and other miscellaneous crops in the United States and Canada were selected at the Food Use Workshop held Sept. 13–15, 2022, in Bloomington, Minnesota. About 175 people attended the three-day meeting, 110 in-person and 65 virtually, including specialty crop researchers, Extension specialists, representatives of commodity and industry groups across the country, and personnel from EPA, USDA, IR-4 plus the AAFC (Agriculture and Agri-Food Canada) that conducts Canadian counterpart of minor use program, and PMRA (Pest Management Regulatory Agency), i.e., Canadian counterpart of U.S. EPA.
For Michigan’s fruit and vegetable interest, the workshop was attended by Michigan State University’s Bernard Zandstra, Sushila Chaudhari, Nicole Soldan, John Wise, Mary Hausbeck, Timothy Miles, Celeste Wheeler, Rufus Isaacs and Lynnae Jess. Representing Michigan grower’s group was Jamie Clover Adams (asparagus) and Christopher Bardenhagen (cherry). Representing a large portion of Michigan greenhouses was Karin Tifft (Mastronardi Produce).
The prioritization process focused on the most critical pest management needs from all disciplines, for each commodity. Participants were provided with a list of 177 pesticides nominated with desired priority of A prior to the food-use workshop. As a group, they ranked products based on availability and efficacy of alternative pest management tools (including ongoing projects for the same need and resistance management), damage potential of target pest(s), performance and crop safety of the chemical in managing the target pest(s), compatibility of the proposed chemical candidate with integrated pest management, uses currently covered by Section 18 emergency exemptions, and harmonization implications due to lack of international MRLs (Maximum Residue Limits).
Based on projected budget appropriations for IR-4 in 2022, only 45 A priority projects throughout the disciplines were selected by consensus. An A priority guarantees IR-4 to begin the field residue program during the following season and complete it within 30 months. The timeline will be shortened when IR-4 joins the company’s petition submission schedule with the expectation that a complete data package be submitted to the EPA in 16-24 months.
In addition to the above projects that require pesticide residue analysis under GLP, 17 H+ (high priority plus) efficacy/crop safety projects have been selected, because potential registrants want to see the data first before IR-4 conducts full residue studies, or IR-4 needs to screen pest control products for new pests, the PPWS (pest problems without solution) projects.
Thirty-two priority projects important for Michigan were selected and one B priority have already been upgraded to A priority status through the priority upgrade process (PUP) (Table 1). In addition, 12 candidate H+ projects for Michigan growers were identified (Table 2). Any additional B priority projects must be upgraded to A priority either by PUP with good justification or regional upgrade, i.e., the crops or the pests are limited to a particular region. At present IR-4 may consider eight upgrades should the budgetary situation become more favorable.
The following new candidate priority A and H+ projects listed are preliminary until affirmed at the IR-4 national research planning meeting on Oct. 24 – 27, 2022. A complete listing can be found on the IR-4 website.
Table 1. Priority A projects for Michigan fruits and vegetables. |
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Group |
Commodity |
Chemical |
Reasons for need |
01AB |
Beet (garden) |
Flutolanil |
Rhizoctonia; per NY me-too request, there is azoxystrobin insensitivity in R. Solani population affecting beet, and is the sole product available:09/19 |
03-07AB |
Onion |
Bifenthrin |
Seedcorn maggot; other treatments have lost registration, chlorpyrifos, and some other treatments are not as effective. |
04-16A |
Lettuce (greenhouse) |
Pyriofenone |
Powdery mildew - disease is not being managed adequately with fungicides currently registered. |
05-16 |
Cabbage (greenhouse transplant) |
Azoxystrobin |
Soil-borne pathogens; there are no other products registered; per NH me-too request: growers have struggled to control root rots on vegetable transplants without fungicide tools; per in, CT and CA me-too request: there are no products labeled for use against root rot; per FL me-too request: needed for disease management for transplant production. |
08-10A |
Tomato (greenhouse) |
Bcs-cw64991 |
Mites: TSSM, citrus and European red mite, broad mite; this material could permit both drip and foliar application for control of a wide range of mites. |
08-10A |
Tomato (processing) |
Inpyrfluxam |
Southern blight (Sclerotium rolfsii); there are active ingredients currently registered for field control of southern blight of tomato but they are not effective; in recent years, we have seen an increase of southern blight likely due to abnormal weather patterns we experience during planting and lack of control of labeled products; having the option of fungicide applications with effective active ingredients when the disease occurs would reduce losses that tomato growers are experiencing due to southern blight. |
08-10A |
Tomato (greenhouse) |
Isocycloseram (ism-555) |
TSSM, thrips, and stink bugs are key insects for greenhouse production; this is in IRAC group 30. |
08-10A |
Tomato |
Tiafenacil |
Annual broadleaf weeds and grasses; as a nonselective herbicide provide good control of broadleaf and grasses before planting the crop and also can be used in row middle during the season. Can be used as an alternative to paraquat. Due to lack of residual, can be used in multiple cropping systems. Improve the control of resistant weeds. |
08-10BC |
Pepper (greenhouse) |
Isocycloseram (ism-555) |
Nothing registered for pepper weevil, the cause for most greenhouses stopping to grow this crop; western flower thrips a significant problem for northeast. |
09B |
Cucumber (greenhouse) |
Bcs-cw64991 |
Mites: TSSM, citrus and European red mite, broad mite; this material could permit both drip and foliar application for control of a wide range of mites; in NY we are not allowed to use abamectin or oberon; so this would be helpful. |
09B |
Cucumber |
Tiafenacil |
Annual broadleaf weeds and grasses; as a nonselective herbicide provide good control of broadleaf and grasses before planting the crop and also can be used in row middle during the season. Can be used as an alternative to paraquat. Due to lack of residual, can be used in multiple cropping systems. Improve the control of glyphosate and ALS resistant weeds. |
12-12A |
Cherry |
Ethaboxam |
Phytophthora species causing root and crown rot and fruit brown rot by lowering population in soil. Fumigation of soil has been highly regulated in ca with numerous restrictions. A need for new modes of action as post-plant treatments because pathogen resistance is known for mefenoxam on cherry and for phosphites on other crops. |
12-12A |
Cherry |
Gf-4031 |
Cherry powdery mildew podosphaera clandestine, powdery mildew is an aggressive disease and multiple active ingredients are needed so management programs can be developed. Currently registered pm-specific products are less effective than conventional, some resistance exists, and more effective pm-specific fungicides are needed. |
13-07A |
Caneberry |
Novaluron |
Spotted wing drosophila (SWD); rotational material; this moa not currently registered for SWD management in caneberry. |
13-07B |
Blueberry |
Tiafenacil |
Italian ryegrass, annual bluegrass (diuron resistant); limited non-selective post herbicides to replace paraquat, or expand efficacy of glufosinate. |
13-07G |
Strawberry |
Flutolanil |
Rhizoctonia, black root rot; per project nomination justification comment: need to cover cranberry, too; per WV me-too request: rhizoctonia is the most important fungal pathogen causing black root rot complex (BRRC) on strawberry together with a few other fungal pathogens; currently there is no effective fumigation or fungicidal option to control rhizoc; flutolanil may be a viable option for managing BRRC. |
13-07G |
Strawberry |
Glufosinate |
Incidence of glyphosate and paraquat resistant ragweed parthenium is rapidly increasing in strawberry fields and there are no registered tools available. Glufosinate is highly effective on this species. Also, green kyllinga is a problematic weed in row middles with limited management options and glufosinate is also effective on this species. |
13-07G |
Strawberry (greenhouse) |
Isocycloseram (ISM-555) |
TSSM and thrips need greenhouse products for rotation. |
15-16 |
Corn (sweet) |
Pyridate |
Broadleaf weeds; per DE me-too request: the short residual control with pyridate should allow for double cropping. |
20B |
Safflower/sunflower |
Afidopyropen |
Lygus hesperus; California safflower growers need the ability to manage lygus in an area wide IPM program that includes surrounding high value crops such as cotton and tomatoes. |
20B |
Safflower/sunflower |
Isocycloseram (ISM-555) |
Lygus hesperus, beet leafhopper, stink bug; this product is needed to manage pests in a cropping system that includes safflower and an areawide IPM approach that manages agronomically important pests in safflower that is in rotation with and is neighboring other high value crops. |
22A |
Asparagus (fern) |
Fludioxonil + pydiflumetofen |
Stemphylium vesicarium; current fungicides include the protectants and the strobilurins which are not adequate and do not provide long-lasting protection. |
25A |
Basil (greenhouse) |
Uniconazole-p |
Growth regulation - without this, some crop plants will bolt under hot greenhouse conditions. |
25AB |
Mint (greenhouse 0transplant) |
Azoxystrobin |
Soil-borne pathogens; there are no products labeled for this use; per NH me-too request: growers have struggled to control root rots on herb transplants without fungicide tools; per in, CT and CA me-too request: there are no products labeled for use against root rot; per FL me-too request: needed for disease management for transplant production. |
25AB |
Basil |
Fludioxonil + pydiflumetofen |
Fusarium; very limited number of fungicides registered for fusarium control on basil; per or me-too request 08/20: fusarium wilt is a significant problem in or, and additional rotation products would be nice to have. |
25AB |
Mint |
Fludioxonil + pydiflumetofen |
Powdery mildew, mint portfolio needs new fungicide actives to be better equipped for disease resistance management. |
25AB |
Mint |
Fluroxypyr |
Prickly lettuce, common groundsel, kochia, bedstraw, tumble mustard, volunteer potatoes, nightshades, field bindweed; fluroxypyr provides control of unique weeds that are challenging to control with other currently registered herbicides in mint production; in rotation year when terbacil cannot be used several common weeds are potentially left uncontrolled; again, fluroxypyr provides control of broadleaf weeds. |
25AB |
Mint (greenhouse) |
Uniconazole-p |
Growth regulation - without this, some crop plants will bolt under hot greenhouse conditions. |
99 |
Hemp |
Cyclaniliprole |
Lepidoptera, whiteflies, thrips, aphids, stinkbugs, aphids; no conventional insecticides are registered for this new crop; per KY me-too request 07/20: AI provides broad spectrum insect management with good IPM fit. |
99 |
Hemp |
Fenpyroximate |
Spider mites, broad mite hemp rust mites; no miticides available. |
99 |
Hops |
Mefentrifluconazole |
Powdery mildew; mefentrifluconazole has documented efficacy against hop powdery mildew. Frac group 3 fungicides are important for management of this disease, being used multiple times per year, as producers must have rotate multiple modes of action for resistance management. Mefentrifluconazole is considered a reduced-risk fungicide, and therefore its use in an overall disease management program will enable this frac group to continue to be used but with less risk to non-target organisms and humans. |
99 |
Hops |
Quizalofop |
Annual and perennial grasses, in particular quackgrass (elymus repens); according to published literature, quizalofop can be a more effective chemical control tool for quackgrass (compared to other active ingredients in the same chemical family). |
Table 2. High priority needs for efficacy/crop safety projects for Michigan fruits and vegetables. |
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Group |
Commodity |
Chemical |
Reasons for Need |
12770 |
Onion (dry bulb) |
Fluazaindolizine |
Stubby root and lesion nematodes; the materials currently labeled for onion (dichloropropene + chloropicrin and oxamyl) have potential environmental concerns and their registration may be at risk in the future: 06/19; additional request received from id for pink rot control, but no supportive data that shows it works: 07/19. |
13453 |
Spinach |
Glufosinate |
It is the only alternative to glyphosate for broad spectrum weed control with little soil residual. Very limited herbicides that work in spinach, table beet, and chard. |
13362 |
Bean (snap) |
Metribuzin |
Currently the label does not allow for rotating to snap beans the following season. Being able to use metribuzin in rotational crops will allow for a more diverse herbicide rotation over a two-year period. It will allow farmers to achieve effective weed control prior to planting snapbeans and improve overall control. |
2801 |
Pea (edible podded and succulent shelled) |
Isocycloseram (ISM-555) |
Seed corn maggot; replacement for chlorpyriphos; seed treatment with neonicotinoids is another option but not always available for all cultivars and planting dates, and residues pose risk to bees; few effective options exist; effective organic options lacking: 08/19. |
13363 |
Watermelon |
Metribuzin |
Currently the label does not allow for rotating to watermelons the following season. Being able to use metribuzin in rotational crops will allow for a more diverse herbicide rotation over a two-year period. It will allow farmers to achieve effective weed control prior to planting watermelons and improve overall control. |
13323 |
Peach |
Flazasulfuron |
Annual broadleaf weeds, yellow nutsedge, annual grasses, lack of alternatives. |
13260 |
Caneberry |
Novaluron |
Lygus hesperus (western tarnished plant bugs) have been causing fruit damage and the pinching of terminals in blackberry and raspberry in Santa Maria and Oxnard, CA, since 2012. Damage have been observed through grower observations over the years and formal testing of exposed lygus to fruit and terminals. Beyond the direct damage to the fruit, lygus bugs are feeding at the expanding tips of the canes, and many times these canes, once fed upon, will split. Split canes consequently produce smaller, less marketable fruit; EPA green: 08/21 |
11128 |
Caneberry |
Terbacil |
Annual and perennial weeds; per AR me-too request: there is a great need for herbicides that are safe on newly transplanted caneberries. |
11611 |
Strawberry |
Quinclorac |
Weed control in between plastic culture rows; to be used along with seeding of annual grass cover crop to eliminate annual weeds from seed; also for use as postemergence weed control in the same situation; needed to control field bindweed in bearing perennial strawberry: 01/17. |
13493 |
Asparagus (fern) |
Fluxapyroxad + pyraclostrobin |
Stemphylium vesicarium; currently registered products include protectants and strobilurins. New, more effective actives are needed. |
13499 |
Asparagus |
Glufosinate |
Broadleaf and grasses (mainly to control glyphosate and ALS resistant pigweed spp.; redroot pigweed and Powell amaranth one of the major weeds in asparagus and hard to control especially when resistant (ALS and glyphosate) biotypes are preset. Glufosinate will help to manage various broadleaf and grasses weeds including pigweed spp. Provide improved weed control compared to carfentrazon. |
13512 |
Hops |
Mb-015 |
Kochia, prickly lettuce, and other annual broadleaves; new mode of action and favorable environmental fate to improve weed management options. |