Reduction of Sclerotium rolfsii damage in Virginia-type peanuts using a combination of tolerant varieties and fungicide

White mold caused by the fungus Sclerotium rolfsii Sacc. is a soilborne disease that causes severe damage to diverse crop plants worldwide, and peanut is among the most sensitive of these. Damage is characterized by plant wilting and rotting of stems and fruit. In Israel, peanut is an important summer crop, but only the Virginia market type is grown, mainly for the in-shell market; the fungicide Nativo (Bayer), which contains tebuconazole 50% and trifloxystrobin 25%, has been found to be the most effective at controlling S. rolfsii . Cultivars grown in Israel are characterized by large pods. The main cultivars are the spreading-type, thick-shelled cv. Hanoch and the bunch-type, thin-shelled cv. Harari. We evaluated the reduction of white mold infection through a combination of chemical treatment and use of a tolerant cultivar. In all three experiments, cv. Hanoch was less sensitive to white mold than cv. Harari. Four treatments during the growing season with Nativo at 1.5 or 2 kg/ha significantly reduced infection. In infected plots, cv. Hanoch gave up to 25.88% higher yield than cv. Harari. In contrast, in uninfected plots, cv. Harari yield was up to 23.3% higher yield than that of cv. Hanoch. In S. rolfsii -infested soils, a combination of the resistant peanut cv. Hanoch with application of Nativo can reduce S. rolfsii infection to very low levels.