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SUMMARY Colletotrichum musae was isolated from banana hands I wk after bunch emergence and in subsequent weeks both from fingers and from crown tissue. Other fungi including Fusarium semitectum and Nigrospora sphaerica were also isolated. Four pre‐harvest sprays of benomyl, each at 1000μg/ml, controlled these fungi on unripe fruit, but unsprayed bunches covered with polyethylene showed rather increased infection rates.Latent infections of C. musae giving lesions on ripe fruit were also largely controlled by the above sprays, but crown rot appearing at this stage was not reduced. One post‐harvest benomyl dip at 250 μg/ml however effectively controlled crown, wound and latent infections. For this reason and also because of the demonstrated risk of benomyl‐resistant isolates of C. musae resulting from pre‐harvest treatment, it is suggested that pre‐harvest spraying is unnecessary.

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In a commercial planting of onion, root and basal rots reduced establishment of sets to 44%. which with 30% basal rot in harvested bulbs, represented an overall numerical loss of potential yield of 69%. Fusarium oxysporum, already present in sets at planting, contributed to poor establishment. Isolation from seedlings grown for sets in virgin soil at three locations yielded infection rates of 80 to 90%. In two field trials to evaluate fungicide treatments mean establishment was 47%. In the f i r s t trial involving dusting of the sets before planting Granosan 200 (benomyl 15% + mancozeb 60%) increased establishment by 28%. reduced basal rot of harvested bulbs by 77% and increased yield by 106%. Benomyl decreased basal rot and increased yields but captan and thiram treatments were ineffective. When bulbs from this trial were stored for six weeks under ambient conditions losses were 94% in controls and 45% in the benomyl + mancozeb treatment, with losses from other treatments intermediate. In the second trial, using pre-planting dips of benomyl the optimum concentration/tinp of 100 M/ml for 15 min, reduced basal rot by 65% and increased yield 54%.

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