Biological control of Botrytis, Aspergillus and Rhizopus rots on table and wine grapes in Israel

One hundred and twenty-nine strains of epiphytic micro-organisms, isolated from table and wine grapes in Israel, were screened for antagonistic activity against Botrytis cinerea on table grapes. Two isolates (Candida guilliermondii, strain A42 and Acremonium cephalosporium, strain B11) were further evaluated for the control of decay in grapes caused by Aspergillus niger and Rhizopus stolonifer. Decay incidence caused by Botrytis cinerea, Aspergillus niger and Rhizopus stolonifer on wounded detached berries was reduced to 8, 14 and 22% respectively, by A42 and to 16, 82 and 60%, respectively, by B11. On small clusters with intact berries, decay was reduced to 30, 22 and 22%, respectively, by A42 and to 48, 39 and 30% respectively, by isolate B11. Both strains survived well under local vineyard conditions and during storage at 0°C and maintained relatively high cell counts on the berries. Field experiments were conducted in 1996, 1997 and 1998, with both table and wine grapes. Vines were sprayed with yeast suspension 2–5 times at 7–10 day intervals and decay was evaluated before harvest (wine grapes) or after storage (table grapes). A42 reduced decay caused by Botrytis cinerea in two of the three seasons in both table and wine grapes, and rots caused by Aspergillus niger in wine grapes were reduced significantly in 1997 and 1998. B11 reduced Botrytis cinerea development in the two years it was tested in wine grapes but in table grapes only in 1996. Morever, it did not control decay caused by Aspergillus niger.