CORESTA Meeting, Agronomy/Phytopathology, Bucharest, 2003, P 02

Thrips pest management tactics for suppressing tomato spotted wilt virus in flue-cured tobacco in Georgia, USA

University of Georgia, Dept. of Plant Pathology, Tifton, GA, USA.

The influence of four foliar insecticide treatments, with and without a preplant tray drench treatment of the plant activator acibenzolar-S-methyl (Actigard), and three tray drench treatments, with and without foliar applications of Actigard, were examined in replicated field plots in 2000-2002. Foliar applications of acephate, Actigard, these two products combined, or spinosad, applied four times had little effect on thrips populations and incidence of tomato spotted wilt virus (TSWV) in Test 1. Only in 2002, when spotted wilt exceeded 60% in the untreated plots, was the incidence of TSWV reduced in the acephate (47.5%) and acephate plus Actigard (46.1%). The overall tray drench effect of Actigard was effective in reducing spotted wilt infection in both 2000 and 2002, but had no effect in reducing thrips populations. Tray drench treatments of imidacloprid (Admire), Actigard, or the combination had lower TSWV in both 2000 and 2002 in Test 2. Four foliar applications of Actigard reduced the seasonal incidence of TSWV. The tobacco thrips, Frankliniella fusca (Hinds), was the predominate thrips species present on tobacco foliage, comprising over 90% of the thrips collected. Between 0.8 to 7.8% of the F. fusca tested positive for non-structural TSWV protein (using ELISA) during the three years.