Integrated Crop Management

Soybean insecticide preharvest interval

Several types of insecticides were applied to soybean during August and early September for control of bean leaf beetle. Four of these insecticides have relatively long-to-moderate preharvest intervals of either 60 days (Ambush and Pounce), 45 days (Warrior), or 28 days (Lorsban). Several questions have been asked about who is responsible and liable for following the preharvest interval for an insecticide if it was custom applied to a farmer's field. The following information is an interpretation of information provided by the Iowa Department of Agriculture in consultation with the Environmental Protection Agency.

What are the Iowa Department of Agriculture regulations regarding this issue?

Section 206.11.3(b) (Distribution or sale of pesticides) states that "It shall be unlawful: For any person to use or cause to be used any pesticide contrary to its labeling or to rules of the state of Iowa if those rules differ from or further restrict the usage." Harvesting a crop before the interval stated on the label would be illegal. So who is liable to follow the label? The applicator of the pesticide is liable. But if the custom applicator has informed the farmer of the preharvest interval then this could mitigate any enforcement actions against the applicator.

Is the custom applicator required to inform the farmer of the preharvest interval?

No, but this would be a sound business practice and wise stewardship of the insecticide.

Are there potential problems with a farmer harvesting soybean before the preharvest interval?

Yes. The Federal Food, Drug, and Cosmetic Act, Chapter IV, Section 402 (2B) states: "A food shall be deemed to be adulterated if it bears or contains a pesticide chemical residue that is unsafe within the meaning of section 408(a)." This means that if any pesticide chemical residue is found on the soybean that exceeds the established pesticide tolerance then it is unsafe. The farmer that hauls soybean to the grain elevator with contaminated residue would be liable for delivering to the marketplace soybean with illegal residues and any other problems they could cause. Unsafe soybean could create many problems at the grain elevator or with potential sales to international markets.

What is the solution to this potential problem?

The custom applicator should document that he or she has informed the farmer of the date of insecticide application to the field and the preharvest interval for the chemical. The farmer should determine when the preharvest interval will expire and not harvest the soybean before the label-stated interval.

This article originally appeared on pages 178-179 of the IC-488(21) -- September 23, 2002 issue.

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