Biological control of plant pathogens in raspberries using beneficial microorganisms, compost teas and nutritional management

From September of 1994 through June of 1995, with the financial assistance of OFRF, Organic Ag Advisors and Aptos Berry Farms conducted research on the biological, nutritional and cultural control of Botrytis and Powdery Mildew an Raspberries at the Aptos Berry Farm on Thompson Road in Watsonville CA The research took place in a raspberry operation that uses an integrated organic and conventional farming system, on a raspberry variety chosen because of it's history of trouble with these plant and fruit pathogens, These raspberries bear fruit in fall and spring, thus giving the opportunity to perform experiments at 2 distinct seasons.


1) Collect and identify the presence of the pathogen and potential biological control microorganisms for the control of Botrytis, Powdery Mildew and Rust on the foliage and fruit of raspberries.

2) Identify the most promising, biocontrol agents and culture them in vitro and in vivo to obtain high populations of these microbes on the surface of the susceptible crop. Monitor the efficacy of establishing these microbes on the susceptible crops and their ability to suppress or control the target pathogen.

3) Identify factors which influence the resistance or susceptibility of particular cultivars of these crops, particularly nutritional and physical characteristics of Susceptible andresistant varieties.

4) Culture compost teas and extracts in standardized species and concentrations for the application to the susceptible plant hosts for the biological and nutritional control of the target pathogens.

5) Identify plant nutrient thresholds for the establishment of pathogen biocontrol agents and the destruction or discouragement of the target pathogen.

6) Utilize organically acceptable nutrients for the management of desirable soil and plant tissue nutrient levels in relationship to the target plant pathogen.

7) Teach organic growers and consultants the techniques and materials necessary to grow & monitor these biocontrol agents on the farm.