J KÖHL, NJ FOKKEMA

Saprophytic microorganisms (bacteria, yeasts or filamentous fungi) were screened for their ability to reduce severity of grey mould (Botrytis cinerea). Isolates of the yeasts Rhodotorula glutinis and Cryptococcus albidus, of the bacteria Xanthomonas maltophilia, Bacillus pumilus, Lactobacillus sp. and Pseudomonas sp., and of Gliocladium catenulatum were found to control grey mould in bean and tomato plants. Their ability to reduce germination of conidia and severity of rot symptoms on detached leaves and to control the disease on whole plants, under controlled conditions was good, consistent and at least similar to the activity of the known biocontrol agent Trichoderma hazianum T39 (non-formulated). The pathogen was applied at a rate of 10-10 conidia/ml. The selected saprophytes were effective in control at concentrations 10 “-10" cells/ml. The yeast isolates were tested at low nutrient level and found effective …