Preharvest sanitisers and fungicides for reducing Penicillium digitatum inoculum on cv. Satsuma mandarin

The efficacy of three sanitisers (didecyldimethyl ammonium chloride, sodium hypochlorite and chlorobromohydantoin) and two fungicides (kresoxim methyl, potassium phosphite), applied as whole-tree sprays prior to harvest, was compared for reducing the number of colony forming units (cfu) of Penicillium digitatum on the surface of cv. Satsuma mandarin fruit. The effects on the cfu of the saprophytic fungi Cladosporium spp. and Epicoccum purpurascens were also examined. The efficacy of the sanitisers and fungicides differed according to the species of fungi. Didecyldimethyl ammonium chloride gave approximately a 75% reduction in numbers of cfu of P. digitatum, Cladosporium spp. and E. purpurascens. Sodium hypochlorite significantly reduced cfu of P. digitatum but did not affect cfu of Cladosporium spp. and E. purpurascens. Kresoxim methyl, potassium phosphite and chlorobromohydantoin exhibited no effect on cfu of P. digitatum and E. purpurascens. However, cfu of Cladosporium spp. was significantly reduced when fruit were treated with potassium phosphite.