Journal of Applied Horticulture. 2005: 7(1): 16-19

Effectiveness of selected fungicides applied with or without surfactant in controlling anthracnose on three cultivars of Euonymus fortunei

Cole, J T; Cole, J C; Conway, K E

Department of Horticulture, University of Arkansas, Fayetteville, AR 72701, USA.

Laboratory and field experiments were conducted in Stillwater, Oklahoma and Fayetteville, Arkansas, USA, from May to August 2000, to determine the effectiveness of different fungicides applied with and without the surfactant Hyper-ActiveTM in controlling anthracnose caused by Colletotrichum gloeosporioides [Glomerella cingulata] on Euonymus fortunei cultivars Emerald Gaiety, Emerald 'n Gold and Emerald Surprise. The fungicides tested were mancozeb, copper hydroxide, trifloxystrobin, chlorothalonil, myclobutanil and azoxystrobin. These fungicides were also incorporated into potato dextrose agar to determine the effective concentration to obtain 50% inhibition (EC50) of C. gloeosporioides mycelial growth. In the field, chlorothalonil and mancozeb were the most efficacious of the fungicides tested. The presence or absence of the surfactant Hyper-ActiveTM in fungicide spray solutions did not affect control of anthracnose symptoms. Cultivars varied in susceptibility to anthracnose. At Fayetteville, less anthracnose symptoms appeared on Emerald Gaiety and Emerald Surprise than on Emerald 'n Gold. However, at Stillwater, disease incidence was similar on Emerald 'n Gold and Emerald Surprise. Mycelial growth in culture was most inhibited by the fungicides myclobutanil and trifloxystrobin.