Various approaches toward controlling sudden wilt of melons in Israel

Control of sudden wilt has been based mainly on methyl bromide fumigation prior to planting. As methyl bromide usage is slated to be prohibited, there is a need to develop alternative control strategies, such as breeding for resistance, grafting, manipulation of irrigation regime, fungicide application, and soil solarization. During the past few years, crosses have been made to introduce resistance from tolerant melon accessions into commercial melon cultivars. Experimental hybrids are being evaluated for resistance and fruit quality. In the field, we have observed Monosporascus sudden wilt incidence on grafted plants to be significantly lower than on non-grafted plants. Thus, grafting can be an effective method of managing sudden wilt of melons. Melon plants have been grown using the usual daily irrigation and a less frequent water supply. In the daily-irrigated plots, initial wilt symptoms appeared 47 days after planting, and the plants eventually collapsed totally, whilst in the less frequently irrigated plots, initial wilt symptoms appeared 60 days after planting and the plants did not collapse totally. The efficacy of 29 fungicides against Monosporascus cannonballus was evaluated in culture. The fungicide fluazinam was effective in both, inhibiting pathogen growth in culture and suppressing disease in the field, although its degree of efficiacy in the field varied. The usual method of soil solarization was ineffective in controlling sudden wilt of melons. However, the disease was effectively suppressed by solarization of a low volume of growth medium or by combining solarization with reduced rates of chemicals.