VARIATION IN THRIPS SPECIES COMPOSITION IN-FIELD CROPS AND IMPLICATIONS FOR TOMATO SPOTTED WILT EPIDEMIOLOGY IN NORTH-CAROLINA

Thrips were surveyed in tomato spotted wilt-susceptible crops in five areas across North Carolina. Tomato, pepper, and tobacco plants in com mercial fields were sampled and 30 species of thrips were collected ov er a 3-year period. The most common species overall was Frankliniella tritici (Fitch). The most common thrips species that are known to vect or Tomato Spotted Wilt Virus (TSWV) were F. fusca (Hinds), and F. occi dentalis (Pergande). Relatively low numbers of Thrips tabaci Lindeman, another reported vector, were collected. The spatial and temporal occ urrence of vectors varied with sampling method, crop species, region o f North Carolina, and localized areas within each region. In a laborat ory experiment, no difference was detected between the ability of F. f usca and F. occidentalis to acquire and transmit a local isolate of TS WV. Based on vector efficiency and occurrence, F. fusca is considered the most important vector of TSWV in tobacco, whereas both F. fusca an d F. occidentalis are important vectors of TSWV in tomato and pepper.