2008 Volume 74 Issue 2 Pages 89-96
Harvested fruit of mandarin orange developed rot caused by green mold (Penicillium digitatum), in plastic greenhouses, orchards, and packing houses in August to September 1993 in Saga Prefecture. When the disease was found, many benzimidazole-resistant strains were present among strains of P. digitatum isolated from packing houses at different locations in Saga Prefecture. Benzimidazole-resistant strains were also frequently detected among strains of P. digitatum that were collected from fruit of very early ripening Satsuma in plastic greenhouses and from orchards before any benzimidazoles were sprayed. Thus, benzimidazole sprays would not have prevented fruit rot in those orchards, strongly suggesting that the benzimidazole-resistant strains were widely prevalent at harvest, resulting in that rot was found on the harvested fruit in the packing house and market an epidemic of rot on harvested fruit. This finding differs from the previous view that the populations of resistant strains are extremely low before harvest.
