Winter Weeds as Inoculum Sources of Tomato Spotted Wilt Virus and as Reservoirs for Its Vector, Frankliniella fusca (Thysanoptera: Thripidae) in Farmscapes of Georgia

• Published in: Environmental entomology 2014-04, Vol.43 (2), p.410-420
• Main Authors: Srinivasan, Rajagopalbabu, Riley, David, Diffie, Stan, Shrestha, Anita, Culbreath, Albert
• Format: Article
• Language: English
• Subjects: adults; alternate host; Animals; crops; Crops, Agricultural - virology; Disease Reservoirs - virology; Disease Transmission, Infectious; females; Frankliniella fusca; Frankliniella occidentalis; Georgia; host range; hosts; immatures; inoculum; inoculum source; Insect Vectors - virology; peanuts; pepper; Plant Diseases - virology; Plant Weeds - virology; PLANT–INSECT INTERACTIONS; population; Population Dynamics; reproduction; Seasons; Species Specificity; Thysanoptera - virology; tobacco; Tomato spotted wilt virus; tomatoes; tospovirus; Tospovirus - physiology; vector reservoir; weeds
• ISSN: 0046-225X; 1938-2936
• DOI: 10.1603/EN13288

Thrips-transmitted Tomato spotted wilt virus (TSWV) has a broad host range including crops and weeds. In Georgia, TSWV is known to consistently affect peanut, tomato, pepper, and tobacco production. These crops are grown from March through November. In the crop-free period, weeds are presumed to serve as a green bridge for thrips and TSWV. Previous studies have identified several winter weeds as TSWV and thrips hosts. However, their ability to influence TSWV transmission in crops is still not completely understood. To further understand these interactions, population dynamics of two prevalent vectors, viz., Frankliniella fusca (Hinds) and Frankliniella occidentalis (Pergande), on selected winter weeds were monitored from October through April in four counties from 2004 to 2008. Peak populations were typically recorded in March. F. fusca and F. occidentalis adults were found on winter weeds and their percentages ranged from 0 to 68% in comparison with other adults. Immatures outnumbered all adults. Microcosm experiments indicated that the selected winter weeds differentially supported F. fusca reproduction and development. The time required to complete one generation (adult to adult) ranged from 11 to 16 d. Adult recovery ranged from 0.97 to 2.2 per female released. In addition, transmission assays revealed that thrips efficiently transmitted TSWV from peanut to weeds, the incidence of infection ranged from 10 to 55%. Back transmission assays with thrips from TSWV-infected weeds resulted in up to 75% TSWV infection in peanut. These whole-plant transmission and back transmission assays provide the basis for TSWV persistence in farmscapes year round.