Monti Vandiver, IPM specialist in Farwell, Texas, is seeing a lot of thrips. “I have seen large numbers of thrips in wheat, which will likely move into adjacent cotton as the cotton emerges and wheat desiccates,” he says. “Cotton will need to be monitored closely from emergence. The first week is critical in thrips management.”

He says farmers may have to act fast to prevent damage. “Insecticide applications made after visual damage occurs are too late to provide adequate protection. We are continuing to refine thrips action threshold, which will take into consideration growing conditions as well as the thrips numbers in the field.”

He says acephate applied at emergence may be necessary if producers used no preventive insecticide seed treatments. “Follow-up applications may be necessary, based on threshold (one thrips per true leaf under good growing conditions or one-half thrips per true leaf under poor growing conditions). If a preventive insecticide seed treatment is used, then subsequent insecticide application should be based on the same threshold, but the thrips population should include immature thrips, which is an indication that the seed treatment is beginning to lose effectiveness.”

Anderson said seed treatments such as Aeris, Cruiser, or Avicta CC should provide 14 to 21 days of protection post-emergence.  “All cotton, regardless of whether growers used a seed treatment, needs to be monitored weekly for thrips,” she said.  

“The best way to tell if the seed treatment has worn off is if you start picking up immature thrips.” She agrees that foliar insecticide applications will be justified with one thrips per true leaf.  “But if the cotton is developing slowly (due to cooler weather), then the threshold should be adjusted to an average of one-half thrips per true leaf.

“Foliar acephate is usually effective; however residual activity is likely less than a week.”

Scott Russell, Extension IPM agent for Terry and Yoakum counties has seen a lot of thrips in wheat fields and cautions cotton farmers to be vigilant in scouting for the pests. “I have been in numerous wheat fields the last two days and the thrips are abundant,” Russell says. “I encourage growers to use a good, complete seed treatment for insect, disease and nematode management. This will help get the crop off to a good start. If producers are planting cotton in the proximity of wheat being carried to harvest, I encourage producers to be alert to possible thrips infestations.”

He says dry winter weather is not usually conducive to high populations of thrips. “But be aware that seed treatments only provide 18 to 24 days of control (depending on rainfall, irrigation and temperature).”

He also cautions farmers about resistant weed management. “Individuals should be using residual herbicides to aid in the management of glyphosate resistant careless weed.”

Cotton planters, Russell says, “are just beginning to roll and peanut planting continues.”

And it’s all taking place in continued dry conditions. “Portions of Yoakum County received up to an inch-and-a-half in isolated spots last Friday,” Russell says. “However, most of the area received about half an inch. Producers are still waiting planting rains for dryland fields.”

 

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