Biological control of Monilinia and Botrytis blights in lowbush blueberries

The purpose of the current study was to identify effective biological controls for Monilinia vaccinii-corymbosi and Botrytis cinerea, two blight pathogens of lowbush blueberry. Commercial biological controls (Mycostop, Actinovate, Prestop, Endofine, Sporodex, Serenade, BlightBan A506 and BlightBan C91) were tested under controlled environment and/or field conditions. The yeasts Cryptococcus victoriae and Rhodotorula graminis were also tested for biological control activity against M. vaccinii-corymbosi in a controlled environment, and both yeasts reduced disease by ≥ 50% compared to an untreated control. Bacillus subtilis QST 713 (Serenade) lowered M. vaccinii-corymbosi infection of vegetative buds to almost 0 at 5 kg/ha and 8 kg/ha with two applications in controlled environment and in the field. These concentrations reduced disease when applied one day post-infection, and Serenade and propiconazole reduced the production of conidia on infected plants when applied five and seven days post-infection. Serenade enhanced conidial germination and did not reduce sporulation of B. cinerea on flowers.