Chlorpyrifos is an organophosphate insecticide (Group 1B; IRAC) used to kill insects and mites on crops, buildings, animals, and other settings. All indoor uses of chlorpyrifos were phased out in the 2000s. Chlorpyrifos products are restricted-use pesticides, meaning sale and use of this chemical is restricted to certified applicators.
Dow Chemical Company received registration from the EPA for chlorpyrifos in 1965 and patented the chemical in 1966. Lorsban and Dursban are two widely recognized trade names for chlorpyrifos from Corteva Agriscience (the agricultural division of the 2017 Dow-DuPont merger). Lorsban is labelled for a number of pests on field crops, horticultural crops (orchards, vineyards, vegetables), and ornamental plants such as Christmas trees.
On February 6, 2020, Corteva announced the end of chlorpyrifos production by 2021. This includes Lorsban and Cobalt, which are commonly used in Iowa for control of field crop pests, especially where pyrethroid insecticides are less effective. Other chlorpyrifos products that are registered trademarks of Dow but distributed by other companies include Eraser, Govern, Hatchet, and Whirlwind.
Corteva’s decision to end production of Lorsban was made based on declining sales of the product, citing statistics showing demand for chlorpyrifos is less than 20% of peak demand in the 1990s.
The good news
Other companies produce chlorpyrifos: ADAMA Agricultural Solutions Ltd., Cheminova (acquired by FMC Corporation), Gharda Chemicals, Ltd., and Platte Chemical Company, Inc. (also Loveland Products, Inc.). Products of these companies are distributed by a number of retail companies. Generic products will remain available for farmers to use.
Other organophosphate insecticides will also remain available for use, and new active ingredients with new modes of action are available to help manage soybean aphid in Iowa: afidopyropen (Group 9D; Sefina Inscalis from BASF) and sulfoxaflor (Group 4C; Transform WG from Corteva) were both approved for use in soybean in 2019.
As of now, the Iowa Department of Agriculture and Land Stewardship (IDALS) has not been formally contacted by Corteva or the EPA regarding the status of Corteva chlorpyrifos products. Once more information is available, we will provide updates regarding future sale, distribution, use, and disposal of products, if necessary.
The future of chlorpyrifos
Chlorpyrifos, like many other pesticides, has been under scrutiny in recent years for children’s health concerns, specifically low birth weight, reduced IQ and attention disorders. The EPA has continued registration despite many attempts to ban or limit use of the product and will evaluate potential risks of chlorpyrifos until the review deadline of October 1, 2022 when a final decision will be made.
The EPA’s registration review process ensures that pesticides will not cause “unreasonable adverse effects” when used according to the label and that there is “a reasonable certainty of no harm from dietary and residential exposure”.
Demand will continue to drop amid regulatory restrictions, including a complete ban in the European Union and California. As of February 6, 2020, it is illegal to sell chlorpyrifos in the state of California and use and possession of chlorpyrifos will be illegal in 2021. Hawaii and New York will ban the chemical by 2022, and Oregon, Washington, Connecticut, New Jersey, and Maryland all have plans to implement a ban in the future.
What does this mean for farmers?
- Among other chlorpyrifos products, Lorsban and Cobalt will not be available from Corteva beyond 2020.
- Chlorpyrifos products from other manufacturers will remain available – see Table 1 for a list of alternative chlorpyrifos products available.
- Organophosphates, including chlorpyrifos, will continue to be essential for IPM of field crops: limited modes of action (MoA) are available, and organophosphates can be rotated with other MoA (e.g., pyrethroids) for resistance management.
- Consider adding sulfoxaflor (Transform) or afidopyropen (Sefina), two new active ingredients, to the rotation for soybean aphid resistance management.
- Watch for news regarding chlorpyrifos in the future: health concerns + declining sales + voluntary cancellations + EPA registration review in 2022 could bring unexpected changes.
- The label is the law! Follow all directions on the label for proper use. This will a) prolong efficacy, b) ensure it is safely used, and c) limit environmental and non-target effects.
Table 1. Alternative chlorpyrifos products registered for use in field crops in Iowa.
|Product Name||Registrant Company||Formulation1||Premix Active Ingredients (IRAC Group #)|
|Stallion Brand||FMC||EC||zeta-cypermethrin (3A)|
|Match-Up||Loveland Products, Inc.||EC||bifenthrin (3A)|
|Warhawk||Loveland Products, Inc.||EC|
|Pilot 15G||Gharda Chemicals, Ltd.||G|
|Pilot 4E||Gharda Chemicals, Ltd.||EC|
|Tundra Supreme||Winfield United||EC||bifenthrin (3A)|
|VESPER||Innvictis Crop Care, LLC||EC|
|VOLTAGE ENDURX||Innvictis Crop Care, LLC||EC||bifenthrin (3A)|
|Yuma 4E||Winfield United||EC|
|Lambdafos||Drexel Chemical||EC||lambda-cyhalothrin (3A)|
|Chlorpyrifos products||Quali-Pro, ADAMA, Winfield United, Drexel Chemical||EC, G|
1EC = emulsifiable concentrate; G = granules
Disclaimer: Table 1 may not provide an exhaustive list of all possible chlorpyrifos products, manufacturers, or distributors, and was updated 2/13/2020 from the Agrian Label Search service. Check with your preferred retailer for product availability or recommendations.