SEASONAL OCCURRENCE OF THRIPS (THYSANOPTERA) ON COWPEAS IN WESTERN ARKANSAS AND NORTHEAST OKLAHOMA

Three thrips species were commonly found in western Arkansas and north east Oklahoma cowllea fields during the 1991 and 1992 growing seasons. These were the tobacco thrips, Frankliniella fusca (Hinds), the flowe r thrips, Frankliniella tritici (Pitch), and the soybean thrips, Seric othrips variabilis (Beach). Earlier planted cowpea fields in each area had higher thrips numbers than later planted fields. Tobacco thrips n umbers tended to be higher during the early stages of the crop when th e plants were small. As plants began to produce blooms, flower thrips numbers increased considerably. Peak newer thrips numbers typically oc curred around two weeks after first bloom. Soybean thrips abundance wa s generally lower than the other common species and had no apparent pa ttern. Chirothrips crassus Hinds and Chirothrips spiniceps Hood also w ere found, but were uncommon.