The yield potential of some of the newer cotton varieties should give growers the opportunity to fine-tune their insect programs to help make the most of those years when conditions are favorable, says Ron Smith, Auburn University Extension entomologist.

The first pest of the season on most growers’ minds is thrips, says Smith, and it has become apparent in recent years that a foliar over-spray is needed.

“It’s influenced by planting date, primarily, but also to some degree by nighttime temperatures and overall growing conditions,” said Smith at the recent East-Central Alabama Row Crops Workshop held in Shorter.

“We’re on the same page as Georgia as far as this is concerned. The seed treatments that are planted in the earlier or mid-season window, from early April until about May 10, would benefit from a foliar over-spray in most years.

“The seed treatments last about 21 days from the date of planting, and that’s often about 10 days short of what we need for thrips control. Temik would last 28-plus days, so we’ve lost about 10 days there,” he says.

What is seen with thrips injury above the ground is also reflective of what is seen underground in the root mass, says Smith.

“We have good research data now that indicates there is a direct correlation to what is growing above ground and what is happening with the root system. That could be where our yield increases are coming from with better thrips control.”

The results of multi-state research projects, says Smith, show that over-sprays are most effective during the plant’s first true leaf, which is about the size of a small fingernail. 

“This is much earlier than we would normally spray if we were just going out and looking. You really can’t see the injury at the time you need to make the spray. Cotton with four or more true leaves typically does not benefit from these over-sprays,” he says.

Either Orthene or the generic products provide the best results, says Smith.

Pyrethroids were shown to be less effective, and some were no better than the untreated control, he adds.