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Chlorpyrifos update (08/30/18)

Chlorpyrifos (trade names Lorsban 4E, Lorsban Advanced, Cobalt, Cobalt Advanced and several generic insecticides) belongs to the organophosphate group of insecticides, IRAC 1B, and is a widely used broad spectrum neurotoxic pesticide for control of many insect pests of field crops.

Chlorpyrifos update

Chlorpyrifos (trade names Lorsban 4E, Lorsban Advanced, Cobalt, Cobalt Advanced and several generic insecticides) belongs to the organophosphate group of insecticides, IRAC 1B, and is a widely used broad spectrum neurotoxic pesticide for control of many insect pests of field crops. Some examples include:

  • Alfalfa – grasshoppers, leafhoppers, armyworms, cutworms, pea aphids, plant bugs
  • Dry beans – aphids, armyworms, bean leaf beetles, caterpillars, cutworms, grasshoppers, leafhoppers, seed corn maggots, spider mites
  • Field corn – cutworms, grubs, seed corn maggot, wireworm, grasshoppers, armyworms
  • Soybean – grasshoppers, Lepidoptera foliage feeders, armyworms, bean leaf beetles, cutworms, soybean aphids, spider mites
  • Sugarbeet – grasshoppers, spider mites, Lygus bugs, sugarbeet root maggots, aphids
  • Sunflower – cutworms, grasshoppers, banded sunflower moths, seed weevils, stem weevils, sunflower beetles, sunflower moths, Lygus bugs
  • Wheat – aphids, grasshoppers, army cutworm, cutworms, wheat midge, cereal leaf beetle

In addition, chlorpyrifos has played an important role as a rotational use product for growers to delay the development of insecticide resistance for some insect pests, such as soybean aphids and spider mites.

The 9th Circuit Court of Appeals recently ordered the EPA to revoke all chlorpyrifos tolerances and cancel all registrations of this widely used insecticide within 60 days.

It is too early in the process to know known how the EPA will react to this ruling or what the outcome will be or if it will affect future insect control. Fortunately, we are at the end of our field season for insect management in 2018. Right now, it is still legal to continue using chlorpyrifos according to label directions for insect pest control in field crops. If chlorpyrifos registrations are canceled, there is usually a window of time provided for growers to use up existing stock. Below is a link to EPA’s website on why and how the EPA would revoke a pesticide tolerance, which includes relevant laws and procedural steps:

https://www.epa.gov/pesticide-tolerances/revoking-pesticide-tolerances

 

 

Janet J. Knodel

Extension Entomologist

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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