Seasonal patterns of adult thrips dispersal and implications for management in eastern Virginia tomato fields

Seasonal flight activity of thrips was examined in commercial tomato fields, Lycopersicon esculentum L., on Virginia’s (USA) Eastern Shore in 2000 and 2001. In each of three regions along the Shore, populations of adult thrips infesting tomato flowers and dispersing within tomato fields were monitored weekly. Frankliniella fusca (Hinds) was the only thrips species captured that is currently considered as a competent vector of Tomato spotted wilt virus (TSWV) in most of the mid-Atlantic US region. Seasonal patterns of F. fusca capture were dissimilar among tomato fields across all regions; yet, more F. fusca were captured between midMay and mid-June in all regions compared with those captured between transplanting and mid-May each year. Despite the relatively low observed dispersal activity of F. fusca before mid-May, the threat of TSWV transmission warrants protection of the crop from immigrating F. fusca from transplanting until the end of marketable fruit set. Frankliniella tritici (Lindeman) was the most frequently encountered thrips species dispersing in tomato fields and infesting tomato flowers. Seasonal patterns of F. tritici capture were similar among tomato fields in all regions in 2000, but were dissimilar among regions in 2001. Dispersal of F. tritici was most pronounced between mid-May and mid-June across all fields in each year. Because F. tritici was the dominant species recovered from tomato flowers, it is likely responsible for cosmetic injury to tomato fruit and should be managed to reduce fruit injury when infestations are highest, between mid May and mid June. r 2003 Elsevier Science Ltd. All rights reserved.