Benomyl, a systemic fungicide used In preharvest treatments to prevent Botrytls and other fungal diseases, metabolizes to carbendazlm (MBC). A study was undertaken to determine if the total residues of MBC of greenhouse and field-grown Douglas strawberries accumulate In fruits after successive fortnightly treatments with a commercial preparation of benomyl. Statistical analysis of the data obtained Indicates that residues of MBC do not accumulate In fruits; on the contrary, they decrease over time.

Residues of benomyl (determined as carbendazim, widely accepted as MBC) and of thiabendazole in Wellspur apples were monitored after the apples were treated postharvest by immersion in a bath with each of the fungicides separately and stored under refrigeration. Whole fruit and pulp analyses were conducted over the period beginning 1 day after treatment and lasting up to 200 days afterwards. Under the conditions described, both benomyl (expressed as parts per million of carbendazim) and thiabendazole were found in the fruits in the following average amounts: 0.44 ± 0.03 and 0.11 ± 0.03 ppm benomyl (as carbendazim) in whole fruit and in pulp, respectively; 0.98 ± 0.10 and 0.39 ± 0.10 ppm thiabendazole in whole fruit and in pulp, respectively.