Ucko, O., Plant Protection Dept., Extension Service, Ministry of Agriculture and Rural Development, Be'er Sheva 84100, Israel
Cohen, S., Dept. of Virology, ARO, Volcani Center, Bet Dagan 50250, Israel
Ben-Joseph, R., Dept. of Virology, ARO, Volcani Center, Bet Dagan 50250, Israel

In the isolated Arava region of Israel, virus epidemics in vegetables were avoided by enforcing a crop-free period of one month during June-July. It was found that the cultivated crops are the major reservoir of viruses, and that during these months the insect vector population and the natural virus sources are low. Therefore, a one-month crop-free period was declared during June-July, and since its enforcement in 1986, no economic damage caused by insect-borne viruses has been recorded.