Effect of fungicides applied as foliar sprays and trunk injections on nut rot of chestnuts caused by Phomopsis castanea in Victoria

Abstract

Summary. Fungicides applied in vitro, as foliar sprays and trunk injections were evaluated for the control of phomopsis nut rot, an important storage disease of chestnuts in Australia caused by Phomopsis castanea. Benomyl, imazalil, prochloraz and propiconazole were most effective in vitro against mycelial growth, with EC50 values 100 µg/mL. Up to 4 foliar sprays of benomyl, or phosphorous acid, applied to trees during the growing season reduced (P<0.05) the incidence of rotted nuts during cold storage in 2 out of 5 trials, or 1 out of 3 trials respectively. In one trial, nut rot was reduced from 42.6% in unsprayed trees to 23 or 23.6% in nuts from trees sprayed with benomyl or phosphorous a..