SEASONAL PREVALENCE OF THE THYSANOPTERA IN AN OKLAHOMA PEANUT ECOSYSTEM AND POTENTIAL FOR TOMATO SPOTTED WILT VIRUS

Field surveys conducted within major peanut, Arachnis hypogaea L., production areas of Oklahoma revealed 23 species of Thysanoptera (thrips). Samples were taken biweekly from 9 May 1989 to 22 August 1989. During the sample period, 4,157 thrips were collected. More thrips were obtained from peanut blooms than from terminals or adjoining field borders. In addition, over 75% of the specimens collected were tobacco thrips, Frankliniella fusca (Hinds), while the western flower thrips, Frankliniella occidentalis (Pergande), represented nearly 10% of the overall population. Both thrips species are confirmed vectors of tomato spotted wilt virus (TSWV) on peanuts. The greatest number of thrips were collected in early July, coinciding with early bloom. The lowest populations were collected in late August, coinciding with the postbloom period. The highest populations of thrips were recorded from South Central Oklahoma. Frankliniella fusca populations were greater in peanut blooms than in terminals or adjoining field borders. This site preference for F. fusca was not evident in F. occidentalis, which preferred border areas over peanut terminals and blooms. From the total population collected, 58.5%, 13.1% and 28.4% were females, males and immatures, respectively. Based on results of this survey, Oklahoma has the potential for TSWV in peanuts. Reasons for low infection rates across the state are hypothesized.