Control of Didymella lycopersici on Tomato Stems with Fungicidal Paints

SUMMARY Slurries made from mixtures of wettable powder formulations of fungicides in water or the mineral oil Actipron were applied to Didymella lycopersici Kleb. stem lesions on glasshouse tomatoes. Benomyl/Actipron completely arrested lesion development, but the other treatments, thiram/Actipron, Actipron, and water with captan, captofol, benomyl, benomyl and maneb, an iodophor, maneb, or thiram did not prevent lesion development. Benomyl/Actipron in the ratio of 1:1·5 of commercial products (wt/vol) gave the most satisfactory control of D. lycopersici stem lesions while minimising phytotoxicity. A fungitoxicant was recovered from tomato stems following application of the benomyl/Actipron mixture. With Actipron/benomyl the uptake of the fungitoxicant by the plants was greater than with the benomyl/water mixture, which was not as effective: it dried to a hard shell and lack of moisture may have impeded uptake of the fungitoxicant.