• By Dominic Reisig •
If you are replanting cotton, keep in mind that the Thrips Infestation Predictor for Cotton predicts that cotton planted in May will be more at risk from thrips than earlier planted cotton.
Although seedlings grow quicker in warmer weather, risk is predicted to increase throughout May as thrips move from wheat and weeds as they dry down to cotton. Because of this, growers should double down on thrips control to avoid delays in crop maturity from thrips damage.
First, be sure to use the highest rate of imidacloprid seed treatment available. Secondly, use an in-furrow insecticide or be prepared to use a foliar insecticide once the first true leaf is visible by peeling the cotyledons.
Generally effective in-furrow insecticide options include Ag Logic (3 ½ to 5 pounds) and Admire Pro (9.2 ounces). Ag Logic at these rates is very effective when used in combination with a seed treatment.
A couple notes about Admire Pro. Since the maximum amount of Admire Pro labeled for soil use in a season is 9.2 ounces, if growers have already applied Admire Pro at planting, they cannot use it to replant.
Also, since resistance has been documented to the insecticide in Admire Pro (and Velum Total), performance can vary. Still, most growers using both a seed treatment and a full rate of Admire Pro (with good insecticide to seed contact) can expect good control.
A good option for thrips control is a full rate of a seed treatment followed by a timely insecticide spray. We cannot emphasize the importance of timeliness.
Even a few day delay can make a huge difference. Sprays target larvae as they emerge from eggs that adults lay in fleshy cotyledons. Therefore, they must be timed when the first true leaf is visible by peeling the cotyledons for maximum efficacy.
Dominic Reisig is a North Carolina State Extension entomologist. He may be reached at dominic_reisig@ncsu.edu.