The effects of topical treatments with 6-pentyl-2-pyrone and structural analogues on stem end postharvest rots in kiwifruit due toBotrytis cinerea

Abstract

The picking wounds in kiwifruit formed by breaking off the pedicels at harvest were treated topically with the naturally occurring lactones 6-pentyl-2-pyrone (6PP), decano-δ-lactone (DL) and 2-deceno-δ-lactone (massoialacetone: ML), and with the synthetic fungicide vinclozolin. 6PP was applied at rates from 0·4 to 4 mg, neat or diluted in oil, water or acetone. 6PP treatments consistently reduced the incidence of Botrytis cinerea storage rots to low levels in both inoculated and naturally infected fruit. For inoculated fruit, control was achieved even when treatment was delayed up to 2 days from inoculation. ML gave significant but lesser control than 6PP, while DL was not generally effective. DL was also less effective than ML or 6PP at suppressing B cinerea inoculum germination in vitro. Much lower rates of vinclozolin (8 or 70 μg) also gave significant control of storage rots. Such topical treatment methods permit control of storage diseases with similar application quantities to currently accepted preharvest fungicide treatments. © 1998 SCI.