Pesticide options in field crops: helping farmers with FQPA (Research Brief #42)

    Recent federal legislation will reduce the number and amounts of pesticides available to farmers. But producers can start planning now for these changes by reducing their reliance on pesticides with the greatest potential for harm to human health and the environment.

    Congress unanimously passed the 1996 Food Quality Protection Act (FQPA) to improve food safety. It amends earlier legislation regulating food safety and tolerances and pesticide registration and use. The FQPA mandates that the Environmental Protection Agency (EPA) reassess all existing tolerances for pesticides taking into account additional sources of exposure and establish safety factors to protect infants and children. A tolerance is the maximum legal level of a pesticide residue on food or animal feed that EPA considers safe.

    FQPA creates a single, health-based safety standard for pesticide residues in food. EPA may lower tolerances by a factor of up to ten for pesticides to protect infants and children. FQPA takes into account the sum of pesticide exposures from food, water, and indoor and outdoor air. FQPA also requires screening and testing for endocrine disruptors-chemicals that affect human growth and development.

    EPA will review highest risk pesticides first-those with the greatest potential for harm. The phase out of these pesticides (called List One pesticides because they are to be reviewed first) will affect growers in the year 2000 growing season.

    “First to be reviewed are pesticides known to directly affect the human
    nervous system, such as organophosphates and carbamates,” says Michelle Miller, coordinator of the Pesticide Use and Risk Reduction project.

    Lower-risk pesticides are on a fast track for review and registration to increase alternatives for producers who have to switch from riskier pesticides. All pesticide registrations will be reviewed on a 15-year cycle.

    The Pesticide Use and Risk Reduction project is funded by pesticide overcharge funds administered by the Wisconsin Department of Justice with matching funds from the UW-Madison Center for Integrated Agricultural Systems (CIAS), and other sponsoring organizations who participate as Project Partners (see sidebar). Project Partners direct the project, identify research priorities in their crop areas, and provide FQPA and pesticide options information to their members.

    Project Partners

    Michael Fields Agricultural Institute
    Wis. Apple Growers Assn.
    Wis. Berry Growers Assn.
    Wis. Corn Growers Assn.
    Wis. Farm Bureau Federation
    Wis. Farmers Union
    Wis. Federation of Cooperatives
    Wis. Fresh Market Vegetable Growers Assn.
    Wis. Ginseng Growers Assn.
    Wis. National Farmers Organization
    Wis. Potato and Vegetable Growers Assn.
    Wis. Rural Development Center
    Wis. Soybean Assn.
    Wis. State Cranberry Growers Assn.

    The Pesticide Use and Risk Reduction project works with teams of researchers and farm organization members to identify profitable options to List One pesticides and share them with farmers. The three teams work on field crops, fruits, and vegetables. The Field Crops Team is co-chaired by Chris Boerboom, UW-Madison Agronomy Department, and Jeff Polenske, Polenske Agronomic Consulting of Appleton, Wisconsin.

    The risk cup concept

    FQPA is changing the way that risk is viewed. In the past, each pesticide had several tolerances assigned to it-one for each crop use.

    “Picture a teacup as holding the amount of pesticide it takes to reach a given exposure limit,” Miller explains. “Before FQPA, each pesticide had several of these risk cups assigned to it for each of its uses, but under FQPA each pesticide will be assigned only one.” All of the uses of a particular pesticide-on crops, buildings, and even on pets-will need to share one risk cup. Pesticides with similar modes of action, like organophosphates and carbamates, may be assessed cumulatively within a single risk cup. This level of analysis will help better evaluate the full risk from exposure to more than one pesticide through food, water, air, and the living environment.

    For example, chlorpyrifos (trade names include Lorsban and Dursban) is a commonly used organophosphate pesticide on List One. In the past, risk was primarily based on single source dietary exposure. The first phase of the EPA assessment will assign chlorpyrifos one risk cup for all uses. The second phase of the assessment will assign one risk cup to the family of chemicals to which chlorpyrifos belongs.

    A proactive response

    “Many producers would like to reduce their use of the riskiest pesticides, and this legislative change means producers will need new information about pesticide options,” says Miller. The table above shows several List One chemicals and some options for replacing them.

    The use of Integrated Pest Management (IPM) in field crops has proven to save producers money and lessen health risks, for example, by reducing pesticide rates in combination with tillage, expanded crop rotations, and other cultural practices. Also, newer and less risky pesticides (Lists Two and Three pesticides) can substitute for List One pesticides.

    Commonly used FQPA List One field crop pesticides and some options
    Pesticides are shown by use, chemical name, and trade name

    Commonly used FQPA List One field crop pesticides and some options

    Pesticides are shown by use, chemical name, and trade name

    Corn rootworm
    Chlorpyrifos-Lorsban, Dursban
    Ethoprop-Mocap
    Phorate-Thimet
    Terbufos-Counter
    Carbofuran-Furadan
    Chlorethoxyfos-Fortress
    Tebupirimphos-Aztec

    Reduced risk options
    Tefluthrin-Force
    Fibronil-Regent

    Field practice options
    Use 75 % label rate at planting; crop rotations; tillage

    Annual broadleaf weeds
    Atrazine;
    Bromoxynil-Buctril
    Cyanazine-Bladex
    EPTC-Eradicane
    Simazine-Princep
    (Note: Loss of triazines may hasten resistance development or weed species shift for other herbicide modes of action. Triazine herbicides are three of a limited number of effective soil-applied broadleaf herbicides.)

    Reduced risk options
    Dicamba-Banvel, Clarity, premixes
    Halosulfuron-Permit
    Primisulfuron –Beacon, premixes
    Flumetsulam-Python, premixes
    For herbicide resistant hybrids:
    Imazethapyr + imazepyr-Lightning
    Glyphosate-Roundup
    Glufosinate-Liberty

    Field practice options
    Crop rotations with cultivtion or early application; variable rate; rotary hoeing; scouting

    Annual grass weeds
    Acetochlor-Harness, Surpass
    Alachlor-Lasso
    Metolachlor-Dual
    EPTC-Eradicane
    Pendimethalin-Prowl
    (Note: loss of acetanilides may hasten resistance development or weed species shifts for other herbicide modes of action.)

    Reduced risk options
    Nicosulfuron-Accent
    Rimsulfuron-Basis
    Difluthiamide-Axiom
    For herbicide resistant hybrids:
    Imazethapyr + imazapyr-Lightning
    Glyphosate-Roundup
    Glufosinate-Liberty
    Sethoxydim-Poast Plus

    Field practice options
    Reduced rate with cultivation or early application; rotary hoeing; cultivation; scouting; cover crops

    Wireworm, cutworm, seed maggot, white grubs
    Chlorpyrifos-Lorsban
    Chlorethoxyfos-Fortress
    Ethoprop-Mocap
    Phorate-Thimet
    Tebupirimphos-Aztec
    Terbofos-Counter
    Diazinon (seed maggot)
    Permethrin (cutworm)-Ambush, Pounce

    Reduced risk options
    Tefluthrin-Force
    Fibronil-Regent
    For cutworms:
    Esfenvalerate-Asana
    Cyhalothrin-Warrior

    Field practice options
    Bait stations; increased tillage

    For more information about the Pesticide Use and Risk Reduction project, contact Michelle Miller at (608) 262-7135, e-mail mmmille6@facstaff.wisc.edu

    EPA also has a toll-free FQPA hotline at 1-888-322-1323 and a World Wide Web site at http://www.epa.gov/oppfead1/fqpa

    Contact CIAS for more information on this research.

    Published as Research Brief #42
    September, 1999