Chlorpyrifos Tolerances Revoked by U.S. Evironmental Protection Agency

Sep 21, 2021

By Adam Varenhorst

In August 2021, a final rule was released by the U.S. Environmental Protection Agency (EPA) for the insecticide active ingredient chlorpyrifos. The rule revoked all tolerances for chlorpyrifos. The tolerances represent the amounts of a pesticide product that are allowed on food while still considered safe. Since all tolerances have been revoked, chlorpyrifos has effectively been removed from the list of insecticides that can be used to manage insect pests in South Dakota crops.

Chlorpyrifos Tolerances

Chlorpyrifos is an active ingredient that belongs to the organophosphate insecticide class (Group 1B). Organophosphates are acetylcholinesterase inhibitors, which means that they work by disrupting a certain part of the insect nervous system. This action leads to the buildup of acetylcholine in the nervous system, which results in overstimulation. While all insecticides should be handled with care, organophosphates can pose serious health hazards if exposure occurs. The human nervous system contains the same parts that chlorpyrifos targets in insects.

The final rule will be effective Oct. 29, 2021, and the tolerances for all commodities will expire on Feb. 28, 2022. At this time, the affected entities include anyone associated with crop production, animal production, food manufacturing and pesticide manufacturing. Chlorpyrifos is also undergoing registration review, which must be completed by Oct. 1, 2022. Any products that have chlorpyrifos residues after Feb. 28, 2022 will still be rendered usable as long as:

Residue that is present was the result of an application of chlorpyrifos that occurred at a time and manner while use was lawful.
Residue does not exceed tolerances that were previously authorized.
Evidence that the products were treated lawfully includes records that verify the dates of application.

Based on the final rule, application of chlorpyrifos in 2022 will result in unlawful residues on crops. For this reason, existing stocks should not be utilized. We will continue to monitor this decision for any changes or clarification of the rule that may affect the use of chlorpyrifos on South Dakota crops.

Source : sdstate.edu

Video: Spring 2026 weather outlook for Wisconsin; What an early-arriving El Niño could mean

Northeast Wisconsin is a small corner of the world, but our weather is still affected by what happens across the globe.

That includes in the equatorial Pacific, where changes between El Niño and La Niña play a role in the weather here -- and boy, have there been some abrupt changes as of late.

El Niño and La Niña are the two phases of what is collectively known as the El Niño Southern Oscillation, or ENSO for short. These are the swings back and forth from unusually warm to unusually cold sea surface temperatures in the Pacific Ocean along the equator.

Since this past September, we have been in a weak La Niña, which means water temperatures near the Eastern Pacific equator have been cooler than usual. That's where we're at right now.

Even last fall, the long-term outlook suggested a return to neutral conditions by spring and potentially El Niño conditions by summer.

But there are some signs this may be happening faster than usual, which could accelerate the onset of El Niño.

Over the last few weeks, unusually strong bursts of westerly winds farther west in the Pacific -- where sea surface temperatures are warmer than average -- have been observed. There is a chance that this could accelerate the warming of those eastern Pacific waters and potentially push us into El Niño sooner than usual.

If we do enter El Nino by spring -- which we'll define as the period of March, April and May -- there are some long-term correlations with our weather here in Northeast Wisconsin.

Looking at a map of anomalously warm weather, most of the upper Great Lakes doesn't show a strong correlation, but in general, the northern tiers of the United States do tend to lean to that direction.

The stronger correlation is with precipitation. El Niño conditions in spring have historically come with a higher risk of very dry weather over that time frame, so this will definitely be a transition we'll have to watch closely as we move out of winter.