Chlorpyrifos is an organophosphate insecticide commonly used on a variety of crops in the state of Minnesota. With development of pyrethroid resistance in some soybean aphid populations, the use of chlorpyrifos has increased in recent years. Since 2010, detections of chlorpyrifos in surface water in Minnesota have also increased. In 2017, the MDA detected chlorpyrifos 19 times in surface water.

It is important to understand the current issues with soybean aphid control and the label requirements for chlorpyrifos application.

 A recorded Webinar for applicators, farmers, and agricultural professionals provides information on proper use of chlorpyrifos, label requirements, soybean aphid control, and pyrethroid-resistant soybean aphids.

View the "Chlorpyrifos use in Minnesota" webinar (YouTube)

Recorded April 8, 2020.

What is Chlorpyrifos?

Chlorpyrifos is a broad-spectrum insecticide used on food and non-food crops, golf course turf, sod farms, and industrial sites in Minnesota. It can also be used in greenhouse and nursery production, wood products, and roach bait stations.


Pesticide Type Insecticide (Group 1B)
Chemical Class Organophosphate
Common Trade Names* Lorsban, Cobalt, Warawk, Govern, Pilot
Registration Status EPA: Registered since 1965
MN: Registered
diagram of chlorpyrifos chemical structure
*No endorsement is implied in the referencing of trade names.

Chlorpyrifos, along with atrazine and acetochlor, has been detected with increasing frequency in Minnesota's surface water, at times at elevated levels. The following sections explain chlorpyrifos’ role in Minnesota agriculture, its impact on Minnesota's environment, and actions being taken to minimize its impacts to water.