Chemical control of crown rot in Queensland bananas

Abstract

The efficacy of benomyl, prochloraz, flusilazole and other fungicides in controlling crown rot, a postharvest disease of bananas, was studied. In experiments with harvested fruit, prochloraz and flusilazole were the most effective fungicides. Benomyl was less effective than prochloraz. In 1 experiment, Fusarium pallidoroseum and a Verticillium sp. were frequently isolated from diseased crowns of untreated fruit. Both fungi were pathogenic and sensitive to prochloraz in vitro, but only F. pallidoroseum was sensitive to benomyl. The Verticillium sp. was consistently isolated from diseased crowns of benomyl-treated fruit. The failure of benomyl to control crown rot adequately in Queensland may be related to the presence of benomyl-tolerant crown rot fungi in the flora of banana plantations. In 2 experiments, prochloraz gave good control of crown rot in fruit stored for extended periods before ripening; however, it failed to give adequate control in a third.