Bees Working With Farmers
Charlotte Coates1, D. Susan Willis Chan1, Erica Shelley1,3, Saira Espinosa2,
Peter Kevan1
Can you imagine a world where bees are working with farmers to protect food crops from pests and disease? The exciting potential of apivectoring (the use of bees to transport beneficial particles) provides a new role for bees and beekeepers in agriculture.
As bees industriously labor, carrying pollen from flower to flower, they also act as vectors, transporting other living microscopic particles. These hitchhikers can be harmful, such as plant or insect pathogens. However, the bees can also carry beneficial fungi and improve the health of the plants they visit.
Many microscopic natural competitors or predators, known as biological control agents, are used to control pests in both conventional and organic farming systems. These biological control agents can be formulated in a powder designed to adhere to bees temporarily. As the bees visit a flower to gather pollen and nectar, the powder falls and can combat any unwanted insect pests or disease organisms that may be living on the flowers or leaves. The use of biological control agents is increasingly popular as they provide an alternative to pesticide use, reducing the likelihood that pest populations will become resistant to chemical pesticides.
Compared to conventional applications such as spray or dusting, apivectoring offers an incredibly efficient way to distribute biological control agents to flowering crops as the bees deliver directly to the flower, which eventually becomes fruit (Figures 1&2). Apivectoring can be used in any bee-pollinated crop system and, of course, provides the layered benefits of pollination to the crop, improving both the health and the yield of the crop. Which type of bee is best suited for the apivectoring (e.g. honey bees, bumblebees, or mason bees) depends on many factors, including the type of crop, field or greenhouse conditions, or temperature at blooming. The research will continue to expand and explore options for a multitude of crops. Already successfully tested and used on orchard, berry, vegetable, seed, and oil crops, the possibilities for apivectoring are numerous2.
The first step in successful apivectoring is to choose a living natural competitor or predator that targets the pest in question. The pests and diseases controlled by apivectoring are molds, bacteria and insects that live in or on the flower or fruit where the bees deliver the biological control agent. The biological control agents that target insect pests are known as entomopathogenic. Others, known as fungal or/bacterial inhibitors, occupy space on the plant, preventing harmful phytopathogens from establishing on the flower or leaf.
Bee-delivered biological control agents are diluted into a powder formula that can consist of many ingredients, chosen specifically for the health of the bees and the pest that is being targeted. The concentration and particle size of the powdered formula are optimized to control the pest and enable the bees to carry it easily. Additionally, if the particle size is too small, bees may asphyxiate. If they are too large, particles will not adhere to the bees’ bodies. Diluting commercially prepared biological control agents is necessary if concentrations of the agent provided by the manufacturer are too high and may impact the bees’ health4. Vegetable-based powders such as corn flour are often used as a diluent. Further research into other types of additives could provide more options or improve the efficiency of delivery.
After preparation of the biological control agent powder, it is placed into a dispenser within the bee colony, pictured in Figure 3. The design of crop protection dispensers allows bees to contact the powder formulation as they exit the hive and avoid contact with the formulation as they enter. This two-way design provides maximum delivery of biological control agents to the crops while minimizing product loss. As they carry out their normal foraging activities, the bees carry microscopic particles which will be deposited on any flower they visit continuously throughout the flowering period.
Apivectoring research originally began and continues to this day in Dr. Peter Kevan’s lab at the University of Guelph. In 2019, Dr. Kevan’s lab expanded on the existing research on protecting greenhouse crops against thrips in Ontario by conducting the first trials on controlling insect pests on greenhouse strawberries2,3,4,5. Figure 4 pictures the team changing the trays of the powdered fungal biological control agent Beauveria bassiana to control insect pests on greenhouse strawberries.
Starting in 2020, the Kevan Lab began a new apivectoring project using honey bees to control grey mold on field-grown strawberries on Ontario farms (https://www.facebook.com/2020BeeVectoring ). The project is measuring how well the biological control agent controls grey mold, how far the bees can disperse it, and whether wild bees are picking it up inadvertently as they visit the strawberry flowers. These questions are answered by carefully taking flower and fruit samples in the field (Figure 5).
In addition, more research on the construction and the design of dispensers to optimize the delivery for different types of bees and hives is ongoing in Dr. Kevan’s lab. A good design disrupts the normal movement of bees as little as possible, is easy and cheap to construct and store, and maximizes the delivery of the biological control agent.
Given the benefits of apivectoring to protect against crop pests without leading to pesticide-resistant populations, we will surely see more research solving some of the remaining challenges that are preventing apivectoring from reaching its full potential in both conventional and organic farming systems. To learn more, please contact the International Organisation for Biological Control (IOBC), the International Commission for Plant Pollinator Relations (ICPPR; https://www.icppr.com/), the Kevan Lab website (link) or visit 2020 Bee Vectoring page.
Research Acknowledgment
The 2020 Bee Vectoring Project is supported by the Seeding Food Innovation Fund of George Weston Ltd.
References
1IPBES 2016. The assessment report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services on pollinators, pollination and food production. Bonn, Germany, Secretariat of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, 556pp. https://www.ipbes.net/sites/default/files/downloads/pdf/individual_cha pters_pollination_20170305.pdf
2Smagghe, G., Boecking, O., Maccagnani, B., Mänd, M., and Kevan P.G. (Editors) 2020. Entomovectoring for precision biocontrol and enhanced pollination of crops: exploiting synergy of ecosystem services. Springer Verlag, Germany.
3IOBC Enkegaard, A (Editor). 2005. Integrated Control in Protected Crops, Temperate Climate. IOBC wprs Bulletin. Vol 28(1)
4Mommaerts, V. and Smagghe, G. 2011. Entomovectoring in plant protection. Arthropod-Plant Interactions. 5:81-95pp.
5Espinosa, S.S., Andrés Sánchez, A., Kevan P.G. and Figueroa, J.R.
1University of Guelph, Guelph, Ontario, Canada
2Universidad Nacional de Colombia, Bogotá, Colombia
3Best for Bees Ltd., Kitchener, Ontario, Canada
