Individual and In-combination Toxicities of Six Fungicides for Controlling Fusarium oxysporum on Cymbidium ensifolium

To select appropriate agents for effective controlling the stem rot disease on Cymbidium ensifolium, toxicities of 6 fungicides, either individually or in combination, were tested in laboratory. All 6 fungicides showed varying degrees of inhibition on Fusarium oxysporum, with EC₅₀ that ranked in the order of prochloraz>difenoconazole>carbendazim or trifloxystrobin>hymexazol or mancozeb. In combination, a synergism between difenoconazole and carbendazim, as well as between trifloxystrobin and carbendazim, was observed. The optimum ratio for the difenoconazole/carbendazim combination was 5/5 with a co-toxicity coefficient of 378.63, while that for trifloxystrobin/carbendazim, 8/2 with a coefficient of 247.80.