Detection of Benomyl Resistance in The Anthracnose Pathogen, Colletotrichum Capsici

Conidial isolates of Collectotrichum capsici were obtained from four field sites in Malaysia. Benomyl-resistant isolates were detected by their mycelial growth on agar containing 100 g/ml benomyl. Resistant isolates were found at three of the four sites examined where benomyl sprays were frequently used. Large differences in the effects of benomyl on mycelial growth of sensitive and resistant isolates were demonstrated; growth of sensitive isolates were completely inhibited at 2.5 g/ml benomyl while the resistant isolates examined, all grew on agar containing 1000 g/ml fungicide. The benomyl-resistant isolates were cross - resistant to thiophanate-methyl and carbendazim. Benomylresistant isolates were just as pathogenic to chillies as sensitive isolates. The implication of these results and other reports of benomyl resistance in Collectotrichum are discussed in relation to disease control.