Chemical control of insect vectors to prevent virus transmission
Studies carried out in controlled conditions (Mason et al., 2000) showed that thiamethoxam (a new neonicotinoid insecticide) could effectively prevent transmission of Tomato yellow leaf curl begomovirus – Sardinia by Bemisia tabaci biotype B (both EPPO A2 quarantine pests). Although the results need be confirmed by field studies, these trials indicated that application of thiamethoxam to tomato seedlings before transplantation, or through irrigation system to newly transplanted tomatoes, could lead to significant reduction of the virus for at least 1 month. It is also acknowledged that chemical applications should be part of integrated management programmes, combining insecticide applications with planting of resistant tomato cultivars and use of physical barriers such as insect-proof nets or ultraviolet absorbing screens.
Field trials (Pappu et al., 2000) were carried out in Georgia (US) to assess the effect of foliar applications of acibenzolar-S-methyl on reducing the impact of Tomato spotted wilt tospovirus in tobacco crops (EPPO A2 quarantine pest). Acibenzolar-S-methyl (plant activator eliciting plant defence) was applied alone or in combination with imidacloprid (insecticide targeting thrips vectors). Results showed that this compound, alone or in combination with imidacloprid could reduce significantly the disease incidence in tobacco fields. However, some phytotoxic effects were observed with treatments applied before transplanting. It was concluded that acibenzolar-S-methyl and imidacloprid could offer useful control of the virus, although further studies are needed to optimise the level of disease reduction and to minimize phytotoxic effects.
Mason, G.; Rancati, M.; Bosco, D. (2000) The effect of thiamethoxam, a second generation neonicotinoid insecticide, in preventing transmission to tomato yellow leaf curl geminivirus (TYLCV) by the whitefly Bemisia tabaci (Gennadius).
Crop Protection, 19(7), 473-479.
Pappu, H.R.; Csinos, A.S.; McPherson, R.M.; Jones, D.C.; Stephenson, M.G. (2000) Effect of acibenzolar-S-methyl and imidacloprid on suppression of tomato spotted wilt Tospovirus in flue-cured tobacco.
Crop Protection, 19(5), 349-354.