Phytopathology (2001) 91, 621-627

Ruth Guetsky, D. Shtienberg, Y. Elad and A. Dinoor (2001)
Combining biocontrol agents to reduce the variability of biological control
Phytopathology 91 (7), 621-627
Abstract: Two biocontrol agents, a yeast (Pichia guilermondii) and a bacterium (Bacillus mycoides), were tested separately and together for suppression of Botrytis cinerea on strawberry leaves. The aims of the research were to determine whether the use of their combination would broaden the environmental conditions under which biological control is effective, and to test the hypothesis that it would reduce the variability of control efficacy under diverse conditions. Applied separately, the biocontrol agents significantly inhibited spore germination, lesion formation, and lesion development at most temperatures, relative humidities, and spray-timing combinations (temperatures: 10, 15, 20, 23, 25, and 30°C; relative humidities: 78, 85, 96, and 100%; and spray-timings: 0, 4, and 7 days before inoculation). However, control efficacy was highly variable, and under certain combinations it was not adequate. Control efficacy achieved by the biocontrol agents applied separately ranged between 38 and 98% (mean 74%) and the coefficient of variation ranged from 9.7 to 75%. The mixture of Bacillus mycoides and Pichia guilermondii suppressed Botrytis cinerea effectively (80 to 99.8% control) under all conditions, and the coefficients of variation were as low as 0.4 to 9% in all cases. Thus, application of both biocontrol agents resulted in better suppression of Botrytis cinerea, and also reduced the variability of disease control. Application of more than one biocontrol agent is suggested as a reliable means of reducing the variability and increasing the reliability of biological control.
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Database assignments for author(s): Yigal Elad, Dani Shtienberg

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
review

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Botrytis cinerea	Strawberry (Fragaria)
Meyerozyma guilliermondii (antagonist)	Botrytis cinerea	Strawberry (Fragaria)
Bacillus mycoides (antagonist)	Botrytis cinerea	Strawberry (Fragaria)