Cornell Grape Pathologist Releases Urgent Update on EPA Mancozeb Proposal

Cornell AgriTech
Viticulture and Enology
Pathology

The EPA has proposed to cancel the use of mancozeb in grapevine due to post-application worker exposure hazards. Read below for more details on how to provide feedback to the EPA directly (comments due SEPT. 16) and/or to our Cornell Grape Pathology team (survey responses due SEPT. 6).

The EPA has proposed to cancel the use of mancozeb in grapevine due to post-application worker exposure hazards (Docket EPA-HQ-OPP-2015-0291 and supporting document EPA-HQ-OPP-2015-0291-0094). The public comment period on this proposal is open until September 16th.

Cornell Grape Pathology is conducting a survey to better understand grape grower habits around the activities EPA cite as risk factors in their decision. Survey responses are due Sept 6th. https://cornell.ca1.qualtrics.com/jfe/form/SV_erKGUlRU2XkorCC

Why is the EPA re-registering mancozeb?

FIFRA is a federal statute that governs how pesticides are registered, distributed, sold, and used in the USA. Recently the EPA announced its intention to come into compliance with the endangered species act, which has led to a FIFRA re-registration review of many multi-site fungicides, including ziram, thiram, febram, captan, and now mancozeb.

Why is the EPA proposing to cancel mancozeb use in grape but not in other fruit crops?

The EPA is proposing to cancel mancozeb in grapevine because of post-application worker health hazards. The specific activities in grapevine production that yield post application hazards above the EPA's acceptable threshold after a single mancozeb application (at maximum single application rate of 3.2 lb AI/acre) are tying/training, hand harvesting and leaf pulling up to 45 days; girdling and turning up for 72 days. The EPA has decided that imposing a REI of such length would preclude the use of mancozeb because it would impede growers’ ability to conduct other production activities. A lower single application rate (e.g., 2.5lb AI/acre) would still result in risks that could not be addressed with a feasible REI. Other orchard crops do not conduct these activities and are thus able to accommodate the mitigation practices (4 day REI and ban on hand thinning) the EPA deems necessary to sufficiently reduce post-application worker health hazards from mancozeb.

How did the EPA come to this decision?

The EPA is by mandate required to do a cost-benefit "BEAD" analysis. The BEAD methodology for mancozeb involves assessing the benefits of its use at the acre-level and reflecting on how growers make pest control decisions. This analysis includes reviewing mancozeb usage data, identifying use patterns, target pests, and the attributes that make it valuable for pest control. BEAD also evaluates the biological and economic impacts of using alternative pest control strategies if mancozeb were unavailable, considering factors like costs, resistance management, and crop yield or quality. The methodology relies on data from university extension services, USDA, grower surveys, public comments, and professional knowledge, with pesticide usage data provided by sources like Kynetec USA Inc.

3 pictures. from left to right, downy mildew on several grape leaves, downy mildew on a cluster of grapes, hand holding a single grape leaf with downy mildew — Several examples of downy mildew on grape leaves and berry clusters.

Does the EPA understand the impacts of banning mancozeb in grapevine?

In their BEAD analysis (supporting doc EPA-HQ-OPP-2015-0291-0094), the EPA cites the following anticipated impacts: "With the loss of mancozeb in grape production, BEAD anticipates that at a minimum, grape growers east of the Rocky Mountains will experience an increased cost of pest control as growers will need to integrate more single site fungicides. The growers would have to rely primarily on captan to control Phomopsis disease and downy mildew and single site fungicides (e.g., myclobutanil) for effective control of black rot increasing the risk of resistance. Further, single site fungicides are generally more expensive than mancozeb (Kynetec, 2021a), resulting in additional costs of fungicide treatment."

What happens now?

The EPA is accepting public comment on their proposed interim decision until September 16th. If you wish to contribute a comment to the EPA on their proposed interim decision, you can either mail or email a letter to the below individuals:

Jean Overstreet (overstreet.anne [at] epa.gov (overstreet[dot]anne[at]epa[dot]gov)), Director, Pesticide Re-evaluation Division

Office of Pesticide Programs, Environmental Protection Agency

1200 Pennsylvania Ave., N.W., Washington, DC 20460-0001

Ben Tweed, Chemical Review Manager: tweed.benjamin [at] epa.gov or (202) 566-2274

EPA is interested in receiving new and relevant information that will inform their BEAD analysis regarding the risk assessment and risk management of mancozeb in the overall grape disease and fungicide resistance management picture. Julius Farado, plant pathologist in residence at the USDA, has shared the below list of information that that the EPA will consider relevant if supported with economic, quantitative, scientific data and recent information (not anecdotal).

Adoption of new sprayer technologies that reduce drift and chemical loading to environment (e.g. X number of growers associated with us have adopted Y technology that reduces drift)
Adoption of decision support systems (e.g. forecasting tool) adopted by growers that reduce fungicide applications (e.g. We invested in weather systems to improve NEWA model use over X acres)
Prevalence of fungicide resistance occurring in your sphere of responsibility (X growers who have reported it, X vineyards tested positive, etc)
Adoption of cultural practices (e.g. Y trellis system) that could help reduce occupational exposure (e.g. % of acres, growers who have adopted new practice)
Survey data conducted from growers and grower meetings on the value of mancozeb
Economic impact analysis relative to disease control and mancozeb in particular (e.g. $ losses suffered when DM or phomopsis went unchecked one year)
Export/import impacts (e.g. MRL/tolerances issues)
Changing weather patterns (e.g. climate change impacts in your region) (e.g. we have experienced X more damaging weather events in Y years than the previous decade).
Extension or otherwise bulletin where mancozeb is the recommended as standard treatment (e.g. mancozeb is recommended in our spray guidelines for X growers who interact with us)

What other PID have the EPA released relevant to grape production?

As of April 30, 2024, the EPA proposes to ban the use of Ziram in grapevine (EPA-HQ-OPP-2015-0568-0111). The EPA is currently reviewing comments received on this decision.
As of April 30, 2024, the EPA (EPA-HQ-OPP-2013-0296-0339), the EPA has proposed to extend the REI for Captan and has reversed its previous decision to reduce the maximum application rate.
- For table grapes: 5-day REI for girdling and turning for grapes grown on T-shaped trellises, no changes to REI for table grapes grown on Y-shaped trellises.
- For wine and juice grapes: 3-day REI for high-contact activities, including tying and training vines as well as hand harvesting and leaf pulling.
- The EPA reversed its previous decision to reduce Captan application rate in grapevine because of stakeholder comments they received.
  - "Stakeholder comments mentioned the need to maintain the 2 lbs. a.i./A application rate for Eastern wine grapes for effective pest control. The comments also mentioned viticulture practice of applying captan to wine grapes early in the season because it interferes with fermentation. Therefore, EPA is proposing longer REIs for wine and juice grapes (rather than reducing application rates). Although these proposed activity-based REIs for grapes result in MOEs less than the LOC of 100, these longer REIs will address most risk concerns for re-entry workers exposed to captan on foliage."

Dr. Kaitlin (Katie) Gold is an Assistant Professor of Grape Pathology, and Susan Eckert Lynch Faculty Fellow, in the Plant Pathology and Plant-Microbe Biology Section of the School of Integrative Plant Science at Cornell University where she holds primary research and extension responsibilities for grape disease management in New York State. Dr. Gold’s Grape Sensing, Pathology, and Extension Lab at Cornell (GrapeSPEC) studies the fundamental and applied science of plant disease and plant-microbe interaction sensing to improve integrated grape disease management.