The cool nights and lower cotton seed vigor has slowed cotton seedling growth making the young cotton plants more susceptible to thrips injury and potential yield loss. They also may delay maturity and this is a deep concern for north Alabama growers. The cotton thrips model (here) continues to forecast heavy thrips pressure in Cherokee County and the Tennessee Valley from mid-to-late May (see attachment with the darker the red indicating heavier thrips pressure).
Cotton planted in mid-May will probably benefit from an automatic foliar application for thrips control at the one-leaf stage but earlier planted cotton needs to be scouted for thrips until the four-to-five leaf stage.
A foliar insecticide should be applied to cotton where an at-plant seed or in-furrow systemic insecticide has been used when 1-3 thrips per plant are counted and immature thrips (wingless) are found. The presence of immature thrips indicates that the at-plant insecticides are no longer working.
Dr. Ron Smith, Alabama Extension cotton entomologist, recommends “Acephate (Orthene) is our most effective thrips insecticide and should be a cotton grower’s number one choice when a foliar thrips material is needed. Bidrin and demethoate are also good options although I am concerned about using Bidrin for thrips and supplies being short later when growers need a good stink bug material. Radiant is another option but more expensive than other thrips control options. No entomologist in the SE recommends bifenthrin for thrips’ control.”