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Poster: Diseases of Plants: New & Emerging Diseases


Reemergence of the torradovirus, Tomato necrotic dwarf virus, in processing tomatoes in the Central Valley of California
O. BATUMAN (1), M. Vasquez-Mayorga (1), J. Nunez (2), L. Hladky (3), W. Wintermantel (3), R. Gilbertson (1) (1) University of California Davis, U.S.A.; (2) University of California Cooperative Extension, U.S.A.; (3) United States Department of Agriculture

In the fall of 2015, processing tomato plants (Solanum lycopersicum) in a late-planted field in Kern County, California had high populations of whiteflies and developed virus-like symptoms including stunting and distorted growth; leaf curling, crumpling and necrosis; and stem and shoot necrosis. The symptoms resembled those induced by Tomato spotted wilt virus (TSWV), but immunostrip and RT-PCR tests were negative for TSWV and other tospoviruses. RT-PCR tests were then performed for Tomato mosaic virus (ToMV), Alfalfa mosaic virus (AMV), Tomato necrotic spot virus (ToNSV), and torradoviruses (family Secoviridae) were performed. The expected size DNA fragments were amplified for ToMV and torradovirus (degenerate primers for RNA-1 and RNA-2), whereas negative results were obtained for AMV and ToNSV. Analysis of the DNA sequences of the PCR-amplified torradovirus RNA-1 and RNA-2 fragments revealed that these plants were infected with a torradovirus that was most similar (~94%) to RNA-1 and RNA-2 of Tomato necrotic dwarf virus (ToNDV). This is the first report of ToNDV in the Central Valley of California, although it was previously reported from the Imperial Valley of California in the 1980s. Surveys to determine inoculum sources and further sequencing and biological characterization of ToNDV isolates in California are in progress.