Fungicide sensitivity of non-pathogenic Fusarium isolate MT0062, a potential biocontrol agent, and induction of benomyl-resistant mutants

摘要

A study was carried out to investigate the sensitivity of non-pathogenic F. oxysporum isolate MT0062 to several fungicides, registered in Japan for tomato and aubergine production. Benomyl tolerant mutants of F. oxysporum were also produced for practical use and ecological assessment. Fungicides tested were benomyl, captan, chlorothalonil, dichlofluanid, flutolanil, mepronil, pencycuron, thiophanate-methyl, thiram, tolclofos-methyl, quintozene and validamycin. Growth rates of F. oxysporum were determined on potato dextrose agar with each fungicide (not exceeding 1% v/v). Chlorothalonil, flutolanil, mepronil, pencycuron, quintozene, tolclofos-methyl and validamycin did not inhibit F. oxysporum growth at up to 1000 ppm. Benomyl tolerant mutants (BR09 and BR11) were selected, which showed growth on media with 100 ppm benomyl. Cross tolerance between benomyl and thiophanate-methyl was observed in the mutants. BR11 had a control effect on vascular diseases of tomato in the greenhouse (93.1% and 94.5%for Fusarium wilt and Verticillium wilt, respectively). However, BR09 gave little control. It is concluded that the benomyl tolerant mutant could be a valuable tool in population dynamics studies of a potential biological control agent.