Suppressive Effect of Organic Farming Materials on the Development of Tomato Gray Mold
Botrytis cinerea infects stems, leaves and fruits of greenhouse tomato and can cause serious economic losses. This study was conducted to develop organic farming control method against tomato gray mold. Twenty two organic farming materials including mineral and plant extracts were screened for the suppressive activity against Botrytis cinerea, in vitro and in vivo. Among the organic farming materials, sulfur, copper, Chinese twinleaf extract and rhubarb extract decreased by 51.7-90% of the spore germination of Botrytis cinerea. Also, gray mold incidence was reduced more than 90% on tomato stems by treating sulfur, seaweed extracts, rhubarb root extracts and Chinese twinleaf extract. After the selected four organic farming materials were applied on tomato cultivated in greenhouse, their control effects against the tomato gray mold were tested. When the water soluble sulfur was foliar-sprayed on the tomato leaves infected by artificial inoculation with spore suspension of Botrytis cinerea, it showed 87.9% of control value. Also, control activity of the water soluble sulfur was paralleled with chemical fungicide, diethofencarb+carbendazim. The above mentioned results indicate the sulfur for-mulation can be used as chemical fungicide alternatives for controlling tomato gray mold in the greenhouse.