Wednesday, 20 November 2002 - 8:30 AM
0907

This presentation is part of : Development and Implementation of Management Systems for Thrips and Tospoviruses

The importance of weed hosts in managing thrips and tospoviruses in field crops

Russell L. Groves1, James F. Walgenbach2, James W. Moyer3, and George G. Kennedy2. (1) USDA-ARS, Plant Protection Unit, Cornell University, Ithaca, NY, (2) North Carolina State University, Department of Entomology, Gardner Hall, Raleigh, NC, (3) North Carolina State University, Department of Plant Pathology, NCSU Box 7616, Raleigh, NC

Wild plant species were systematically sampled to characterize reproduction of thrips, the vector of Tomato spotted wilt virus (TSWV) and natural sources TSWV infection. Thrips populations were monitored on perennial, biennial, and annual plant species over 2 years at six field locations across North Carolina. The tobacco thrips, Frankliniella fusca, was the most abundant TSWV vector species collected comprising > 95% of vector species in each survey season. Sonchus asper, Stellaria media, and Taraxacum officianale consistently supported the largest populations of immature F. fusca. In random surveys across 12 locations in North Carolina, TSWV infection was documented by ELISA in 35 of 72 (49%) common perennial (N=10), biennial (N=4), and annual (N=21) plant species across 18 plant families. Estimated rates of TSWV infection were highest in C. vulgatum (4.2%), Lactuca scariola (1.3%), Molluga verticillata (4.3%), Plantago rugelli (3.4%), Ranunculus sardous (3.6%), S. asper (5.1%), S. media (1.4%), and T. officianale (5.8%). Most perennial plant species were often only locally abundant while many annual species were more widely distributed. Perennial species, including P. rugelli and Rumex crispus, remained TSWV infected for two years in a small plot field test. Where these perennial species are locally abundant, they may serve as important and long lasting TSWV inoculum sources. These findings document the relative potential of a number of common annual, biennial, and perennial plant species to act as important reproductive sites for F. fusca and as acquisition sources of TSWV for spread to susceptible crops.

Species 1: Thysanoptera Thripidae Frankliniella fusca (Tobacco thrips)
Keywords: weeds, tomato spotted wilt virus

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