Optimization of foliar-applied formulations for the control of tobacco whitefly Bemisia tabaci, under field conditions
1990
Kanokporn Ounchaichon | Montri Rumakom | Swang Wangboonkong (Department of Agriculture, Bangkok (Thailand). Entomology and Zoology Div.)
Population studies of tobacco whitefly, Bemisia tabaci (Gennadius), have been conducted in the cotton growing area at Nakonsawan during 1987-1989. The whiteflies were sampled by using random methods, leaves were taken from the upper, mid and lower parts of the plants and counted for immature stages. The adult whiteflies were sampled by using yellow sticky traps. Distribution of adults, eggs and nymphs of B. tabaci among and within the cotton plants showed a strong tendency for aggregation. The climatics was found to be the main epidemic factors for B. tabaci in Thailand. Parasitism was minor mortality factor in the field. The toxicological studies of some insecticides, two mineral oils, vegetable oil and its mixture formulations in order to improve the formulation for persistence and stability under field condition were investigated. There was an indicator of increase in percentage mortality of B. tabaci after exposure to the mixture formulations between oils and insecticides compared with individual tested due to the additional suffocation activity of these oils. The physical properties and activities of those oils solvent viscosity. The optimization for formulations of oils and insecticides were then taken into consideration in order to improve control strategies.
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