Seasonal Occurrence of Thrips (Thysanoptera) on Cowpeas in Western Arkansas and Northeast Oklahoma

Three thrips species were commonly found in western Arkansas and northeast Oklahoma cowpea fields during the 1991 and 1992 growing seasons. These were the tobacco thrips, Frankliniella fusca (Hinds), the flower thrips, Frankliniella tritici (Fitch), and the soybean thrips, Sericothrips variabilis (Beach). Earlier planted cowpea fields in each area had higher thrips numbers than later planted fields. Tobacco thrips numbers tended to be higher during the early stages of the crop when the plants were small. As plants began to produce blooms, flower thrips numbers increased considerably. Peak flower thrips numbers typically occurred around two weeks after first bloom. Soybean thrips abundance was generally lower than the other common species and had no apparent pattern. Chirothrips crassus Hinds and Chirothrips spiniceps Hood also were found, but were uncommon.