Tomato yellow leaf curl virus (TYLCV) is the most frequently occurring virus in tomatoes in the Middle East, and the most harmful one. It is transmitted solely by the whitefly Bemisia tabaci (Gennadius). Within 4-6h of inoculative feeding, a whitefly can transmit TYLCV to a healthy plant with 80% probability. The symptoms are apparent after two to three weeks whereupon fruit-set is effectively terminated. The only means of controlling TYLCV is by controlling the whitefly. Until 1990 this was exclusively by insecticides. Starting in 1990, growers of greenhouse tomatoes in Israel began adopting insect exclusion screens to prevent inoculation of TYLCV. This article reports on the methods used in the search for efficient screening materials and presents data on their relative efficiencies in excluding B. tabaci and several other greenhouse pests. Ten materials were tested, of which five were found to be effective in excluding B. tabaci under laboratory conditions. This number was reduced to three following field trials and trials in commercial tomato greenhouses. These materials are now in widespread use in Israel: by 2000 practically all table tomatoes in Israel were grown under exclusion screens. The use of exclusion screens has been shown to be an economically viable pest management method.

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An efficient method for rapidly mass‐screening insecticides for use against sap‐feeding virus vectors is presented with a case study of 30 chemicals. The method permits large numbers of insecticides to be tested simultaneously and relatively inexpensively in a sequence of laboratory bioassays. The sequence is designed to find the most effective pesticide at the lowest concentration giving control without phytotoxicity. The system was derived to test candidate insecticides to control tomato yellow leaf curl virus vectored by the tobacco whitefly, Bemisia tabaci Gennad., the most serious pest of greenhouse and field tomatoes in the Middle East. Although the insecticides were all more efficacious in the laboratory than in the field, bioassay results were highly correlated with results from field trials, giving high confidence that the screening process selected only the most efficacious insecticides. Most of the insecticides accepted by the screening process have since been adopted by vegetable growers in Israel. The method is not intended to eliminate field efficacy trials, but to reduce the number of trials and treatments that need to be performed, thereby reducing costs. The method provides for the optimization of application rates which will contribute to the expected life of insecticides before resistance develops, and will also help to reduce environmental contamination. In addition, the method is suitable for estimating relative efficacy for pesticide benefits assessments, a required part of the (re‐)registration process for pesticides in some countries. Although developed for screening insecticides against virus‐transmitting sap‐feeding insects, the method could be modified to assess the efficacy of insecticides in controlling other insect pests.

An efficient method for rapidly mass-screening insecticides for use against sap-feeding virus vectors is presented with a case study of 30 chemicals. The method permits large numbers of insecticides to be tested simultaneously and relatively inexpensively in a sequence of laboratory bioassays. The sequence is designed to find the most effective pesticide at the lowest concentration giving control without phytotoxicity. The system was derived to test candidate insecticides to control tomato yellow leaf curl virus vectored by the tobacco whitefly, Bemisia tabaci Gennad., the most serious pest of greenhouse and field tomatoes in the Middle East. Although the insecticides were all more efficacious in the laboratory than in the field, bioassay results were highly correlated with results from field trials, giving high confidence that the screening process selected only the most efficacious insecticides. Most of the insecticides accepted by the screening process have since been adopted by vegetable growers in Israel. The method is not intended to eliminate field efficacy trials, but to reduce the number of trials and treatments that need to be performed, thereby reducing costs.The method provides for the optimization of application rates which will contribute to the expected life of insecticides before resistance develops, and will also help to reduce environmental contamination. In addition, the method is suitable for estimating relative efficacy for pesticide benefits assessments, a required part of the (re-)registration process for pesticides in some countries. Although developed for screening insecticides against virus-transmitting sap-feeding insects, the method could be modified to assess the efficacy of insecticides in controlling other insect pests.