Study finds no consistency in efficacy of recovery sprays on auxin injury on cotton

Jan 08, 2020

The synthetic auxin herbicides 2,4-D and dicamba are commonly used for management of glyphosate-resistant and other troublesome weeds. Because of this trend, growers across the Cotton Belt are turning to auxin-resistant cotton. Since the release of auxin-resistant cotton in 2015, the market share has grown to more than 85% in the United States. However, spraying with 2,4-D can be harmful to dicamba-tolerant cotton and spraying with dicamba can cause injury to 2,4-D-tolerant cotton, resulting in yield and economic losses for the cotton producer.

In the webcast "Efficacy of Recovery Sprays to Auxin Injury on Cotton," James Griffin summarizes two studies from 2018 and 2019 that evaluated the effectiveness of available commercial products to recover cotton plants from reduced dicamba and 2,4-D rates when injured at first-bloom stage. Researchers evaluated numerous sprays by assessing the amount of injury and recovery as well as combined lint yields and average boll counts.

No recovery treatments were able to regain yields compared with untreated plots for either 2,4-D or dicamba. Numeric yield gains were shown for almost no recovery sprays over the auxin-only treatments. The trends were inconsistent at best from year to year.

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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.