Control of Colletotrichum acutatum in strawberry under laboratory, greenhouse, and field conditions

Freeman, S., Nizani, Y., Dotan, S., Even, S., and Sando, T. 1997. Control of Colletotrichum acutatum in strawberry under laboratory, greenhouse, and field cond itions. Plant Dis. 81:749752. Various fungicides and a heat treatment were assessed for their ab ility to control strawberry anthracnose caused by the fungus Colletotrichum acutatum under laboratory, greenhouse, and field conditions. The effective dose causing 50% inhibition of mycelial growth (ED 50) was 30.5, 12.2, 0.2, 0.15, 0.05, 0.07, and 0.05 µg/ml for the fungicides folpet, captan, propiconazole, difenoconazole, combined prochloraz-Zn/folpet, prochloraz-Zn, and prochloraz-Mn, respectively. In laboratory experiments, infection in segments of strawberry runners treated with prochloraz-Zn reached 60%, which was significantly reduced as compared to combined prochlorazZn/folpet (90%), captan, folpet, and water controls (100%). In the greenhouse, numbers of naturally infected transplants killed were significantly reduced by all f ungicides and the heat treatment (5 min at 49°C) as compared to the non-treated control. Prochloraz-Zn was the most effective chemical control treatment but did not differ significantly from the heat treatment. In field experiments conducted during 1995 and 1996, numbers of naturally infected strawberry transplants killed were significantly reduced by all f ungicide treatments relative to the nontreated control. Percent reduction of transplant mortality in the field was 93.3, 93.1, 66.7, 37.7, and 29.1 for prochloraz-Mn, prochloraz-Zn, combined prochloraz-Zn/folpet, propiconazole, and difenoconazole, respectively.