Chlorpyrifos update for vegetable crops in 2024

Zsofia Szendrei<szendrei@msu.edu>, Michigan State University Extension, Department of Entomology, and Ben Werling<werlingb@msu.edu>, Michigan State University Extension - February 08, 2024

Chlorpyrifos can be used on all labeled vegetable crops in 2024.

A hand holds a cutworm larvae with a crooked asparagus spear growing up from the ground in the background. — Chlorpyrifos is effective at preventing cutworm feeding that causes asparagus spears to crook. Photo by Ben Werling, MSU Extension.

The insecticide chlorpyrifos was an important tool for a variety of vegetable crops including brassica root crops, leafy brassicas, asparagus and onions. In 2022, the use of this insecticide was canceled. However, in February 2024, the U.S. Environmental Protection Agency reinstated all tolerances—vacating the past rule—as the result of a December 2023 court ruling.

This means that at present, growers of crops that have been on the label in previous years can apply this insecticide consistent with label directions without any violation. Growers with existing stocks of chlorpyrifos may use them according to the label. Retailers, distributors and suppliers may sell currently registered products containing chlorpyrifos. Note that many manufacturers voluntarily canceled their registration to produce chlorpyrifos. This means that new product will only be available through Gharda, Drexel or Loveland.

This reinstatement of all tolerances is temporary. A final decision is expected within the next year, which is expected to revoke tolerances for all but 11 crops, which include alfalfa, apple, asparagus, tart cherries, citrus, cotton, peach, soybean, strawberry, sugar beet and wheat. The situation will probably change beyond this timeline, given the issues around its use.

A hand propping up a turnip plant. — Chlorpyrifos is uniquely suited to prevent cabbage maggot tunneling in brassica root crops like turnips, radishes and rutabagas. Photo by Ben Werling, MSU Extension.

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