Botrytis blossom blight in greenhouse tomato crops was causing up to 15 per cent reduced yield for an organic grower. Botrytis causes blossoms to drop, reducing fruit growth and overall yield.
Action Plan: Perennia horticulturist Rachael Cheverie worked with Pleasant Hill Farm on Nova Scotia’s south shore for two years testing the efficacy of using bee vectoring to deliver the beneficial biological agent Endophyte (Clonostachys rosea) to combat Botrytis blossom blight in greenhouse tomato crops. One tomato greenhouse was the control and used its normal hive. Another tomato greenhouse used Biobest’s Flying Doctor Hive which has a small attachment the bees walk through picking up the product on their legs and body, ready to deposit it on the blossoms when pollinating. When deposited by the bees the product takes up space on the blossoms, making it harder for disease and fungi to take up residence and cause blossom damage, which has been significant. There is one insecticide ‘Botanigard’ currently registered for use in Canada using this delivery mechanism and it works very well. “We looked at the research done by Bee Vectoring Technologies (BVT) on Endophyte and felt it was very well suited for greenhouse growers experiencing this yield loss,” said Cheverie.
The Result: The grower recorded higher yields than in the control greenhouse, and collected blossoms that were sent to Dr. John Sutton of BVT in Ontario, showed significant colonization by the beneficial fungi Endophyte. In year one, the treated house had no blossoms with Botrytis while the untreated house had 12 per cent of diseased blossoms. “We don’t have the data from the second year completed yet, but given the first year results, we expect them to be positive and we are hopeful that the use of bee vectoring will to expand to other crops and biocontrol products,” said Cheverie.