More info BEE better solution than droneshttps://www.greenhousecanada.com/its-all-about-the-delivery/
This is only a portion of the artical worth the read
Bee Vectoring Technologies (BVT) in Ontario has developed a patented system that uses commercially-managed bees to deliver beneficial microorganisms to flowers. Bumblebees are preferred for greenhouse, select outdoor and some specialty crops, while honeybees are best for open fields. Active at lower temperatures than honeybees, bumbles can also be used in early spring or winter crops. Their larger size carries more microbes as well.
BVT’s dispenser system is incorporated into the lid of the commercial hive. The system includes a removable tray (the Vectorpak) that is pre-charged with Vectorite powder plus the beneficial microbe. The powder sticks to the bees as they leave the hive through the dispenser, and it is carried to and deposited into the flower. Flowers are a common entry point for a range of disease-causing organisms and a preferred habitat for many pests (like thrips), so this targeted delivery of disease-suppressive or insect-active microorganisms can be highly effective.
Currently, BVT utilizes a strain of Clonostachys rosea (BVT-CR7) as the primary ‘active’ in their system. A known antagonist and mycoparasite of several plant diseases, the fungus can also grow endophytically within plants and activates the plant’s own defense mechanisms. This can significantly reduce the incidence of Botrytis on fruit (comparable to synthetic fungicides), enhance productivity in greenhouse tomatoes and field-grown strawberries, and improve the shelf-life of harvested fruits. The fungus also suppresses other necrotrophic diseases such as Sclerotinia and Monilinia, and is effective against pathogens such as Alternaria, Phomopsis and Anthracnose.