Study of Joint Action of Mixture Fungicides on Two Leaf Spot Disease of Rubber Trees

The joint action of mixture fungicides on Colletotrichum gloeosporioides Penz. Sace and Corynespora cassiicola (Berk and Curt.) of rubber trees were tested using cross filter paper strip method. The results showed that among 14 combination of 9 kinds of fungicides, most mixture fungicides had additive effect. The commixture of azoxystrobin and chlorothalonil, imazalil and chlorothalonil, bromothalonil and chlorothalonil, myclobutanil and mancozeb had synergistic effect. The commixture of imazalil and mancozeb had significantly antagonistic effect. The inhibition zone analysis found that prochloraz was the most effective against two pathogens, followed by myclobutanil, imazalil and bromothalonil.