Characterization of Frankliniella fusca dispersal and Tomato spotted wilt virus incidence within fields from wild plant hosts
Beaudoin AL, Kennedy GG
North Carolina State University, Department of Entomology, Raleigh, NC, USA.
Correspondence: alparodi@ncsu.edu
Spatial dispersal patterns of Frankliniella fusca (Thripidae), a vector of the tomato spotted wilt virus (TSWV), are not well understood. A study was conducted in three fields of bare soil in North Carolina to determine if the number of adult F. fusca caught on yellow, sticky traps exhibited a gradient varying with distance from a natural weedy source containing known hosts of F. fusca. Yellow, sticky aerial traps were placed 0.76 meters above the soil in recently disked fields. The traps were placed in a grid and the nearest potential sources of thrips on one or more edges of each field were identified. Traps remained in the field for one week and were collected before any vegetation emerged in the field. The number of F. fusca per trap was determined. The data revealed no gradients in numbers of thrips per trap over distances of up to 500 meters from a potential thrips source. In late July, a second study was conducted in three tobacco fields to determine if TSWV incidence exhibited a gradient with changes in distance from potential thrips and TSWV sources. Rows of tobacco plants were visually scored for the presence of TSWV every 15.24 meters, resulting in a grid. The nearest potential sources of thrips and TSWV were identified. No gradient in TSWV incidence was found in distances of up to 200 meters. These studies suggest that management of weed hosts of TSWV around field margins may not be an effective strategy to reduce spread of tomato spotted wilt virus into susceptible crops.
