Chlorothalonil, Trifloxystrobin, and Mancozeb Decrease Anthracnose Symptoms on Three Cultivars of Wintercreeper Euonymus

Abstract

The effectiveness of chlorothalonil, mancozeb, and trifloxystrobin applied alone or in rotations of two or three fungicides to control anthracnose symptoms caused by Colletotrichum gloeosporioides was evaluated on three cultivars of field- and container-grown wintercreeper euonymus (Euonymus fortunei) during the 2001 growing season. Studies were conducted at Stillwater, Okla.; Fayetteville, Ark.; and Park Hill, Okla. Rooted cuttings of wintercreeper euonymus `Emerald Gaiety', `Emerald 'n Gold', and `Emerald Surprise' were transplanted from 1-gal plastic containers into field soil at the Oklahoma State University Nursery Research Station and at the University of Arkansas Horticulture Farm on 10 May 2001. In a parallel study, recently transplanted rooted cuttings of the same cultivars in 1-gal pots containing substrate consisting of pine bark and sand were placed in a shadehouse under 30% shade at Stillwater and Fayetteville and 73% shade at Park Hill on 11 May 2001. `Emerald Gaiety' had fewer disease symptoms than `Emerald 'n Gold' or `Emerald Surprise' in the field and in containers at Stillwater and Fayetteville. At Fayetteville, mancozeb applied alone or in rotation with chlorothalonil or trifloxystrobin provided better anthracnose control than treatments without mancozeb, but no fungicide eliminated anthracnose symptoms. Application of fungicides in rotations that include mancozeb and use of resistant cultivars can help decrease anthracnose symptoms.