CONTROL OF PRE-AND POSTHARVEST FRUIT ROT OF RASPBERRIES BY FIELD SPRAYS
From 1970 to 1975 several systemic fungicides were compared as preharvest sprays with the non-systemics captan, chlorothalonil and anilazine in raspberries for fruit rot control. Considerable rot developed within 48 hours after harvest, even though the incidence of fruit rot in the field was 1% or less. The fungicides had little or no effect upon marketable yield or berry size. Field sprays of several fungicides were effective in increasing the holding quality of the fruit. In general, captan appeared most effective for total rot control. Captan was the only fungicide which reduced Rhizopus when the incidence of this fungus was high. When Rhizopus was a minor contributor of rots no fungicide showed a significant effect upon the fungus. Initially, benomyl and thiabendazole reduced Botrytis while captan and thiophanate did not. In the years 1971 to 1974 all fungicides reduced Botrytis. But, in 1975 only captan and LFA 2043 reduced Botrytis indicating that some resistance may have developed. It is suggested that if the crop is to be harvested mechanically and the fresh market expanded that future control of fruit rots in raspberries will have to increasingly depend on the development of resistant cultivars coupled with the use of broad spectrum fungicides or with mixtures or mixed regimes of systemic and non-systemic fungicides along with reduced time intervals between spray applications during flowering.
Freeman, J.A. and Pepin, H.S. (1976). CONTROL OF PRE-AND POSTHARVEST FRUIT ROT OF RASPBERRIES BY FIELD SPRAYS. Acta Hortic. 60, 73-80