Dinoor, A.

Biocontrol of Botrytis cinerea by a mixture of a yeast (Pichia guilermondii) and one of two bacterial isolates (Bacillus mycoides) was followed during three years of commercial-like greenhouse experiments. Establishment and survival of the yeast and the two bacterial populations on strawberry leaflets and fruitlets were recorded in two experiments. Populations of the bacteria did not differ significantly in separate applications as compared to those in a mixture with the yeast. Similar results were obtained for the yeast. Moreover, in three out of 27 comparisons the yeast populations in the mixture were significantly higher than when applied alone.
Application of the mixture resulted in significant disease reduction as compared to the control treatments. In one experiment, the biocontrol agents applied alone, reduced the number of diseased fruits by 50% whereas their mixture resulted in 75% reduction and additive disease control. In a second experiment, the mixture between the same yeast isolate and another bacterial isolate resulted in synergistic disease suppression as compared with their separate application.