Management and cross-infectivity potential of Colletotrichum acutatum causing anthracnose on bell pepper in Florida

Abstract

Early anthracnose caused by Colletotrichum acutatum has become an increasingly serious disease on green, unripe bell pepper fruit in Florida. This contrasts with earlier reports of anthracnose occurring on bell pepper primarily as a ripe-rot disease of mature, colored pepper fruit caused by Colletotrichum gloeosporioides. Management of anthracnose on green bell pepper fruit using fungicides and a commercial inducer of systemic acquired resistance, acibenzolar-S-methyl (ASM), was evaluated during three seasons. In two of the three trials, all the fungicides tested including azoxystrobin, fludioxonil + cyprodinil, mancozeb, famoxadone + cymoxanil, copper hydroxide, and ASM significantly increased the number of marketable fruit compared with control plants. These trials identified fungicides that could contribute to a successful pest management program on pepper for controlling anthracnose caused by C. acutatum. The cross-infectivity potential of C. acutatum was investigated on tomato and strawberry by in vitro and field inoculation. Anthracnose lesions formed readily on wound-inoculated detached fruits of all hosts in in vitro assays. Under field conditions, after inoculation, anthracnose lesions occurred on pepper fruit but no lesions of anthracnose were found on either ripe or unripe tomato or strawberry fruit in adjacent plots.