Apivectoring Technology and a Heartfelt Thank You!
By: Elina L. Niño
As the UC Davis series comes to a close I wanted to devote this short and sweet final article to a fun topic that I didn’t get a chance to talk about, but which still very much holds my interest: Apivectoring! This simply means using bees, specifically from genus Apis, to deliver a biocontrol agent for controlling a variety of pests and pathogens associated with crops. I first learned about this technology from Dr. Frank Zalom, now retired extension specialist here at UC Davis. He was involved in projects using honey bees to deliver biocontrol agent Trichoderma spp. for control of Botrytis on strawberries in Southern California. He explained a fairly simple, but sophisticated process and I was hooked. I submitted a couple of proposals for projects primarily targeting brown rot blossom blight, a potentially devastating disease (caused by Monilinia laxa) occurring during almond bloom. Considering the impact that the almond industry has on California agriculture and the beekeeping industry we really wanted to focus our efforts on bringing this technology into the almond orchards. The incidence of disease increases during particularly wet blooming season and growers must rely on use of fungicides for control. The goal of the project was to boost bloom coverage using honey bees already in the orchards for pollination, potentially reducing the need for fungicide sprays and improving pollinator protection, as well as minimizing development of resistance in the almond pathogens. As it happens often, my first couple of proposals were rejected, although the reviewers had many valuable points of input for improving the project. I reached out to my UC Davis colleagues Dr. Florent Trouillas (a plant pathologist) and Dr. Rachel Vannette (an entomologist and a microbiologist) and we applied again. This time we received seed funding from UC Davis via the Academic Federation Innovative Developmental Award and the Almond Board of California.
But before we go any further, let me explain what is apivectoring. It is a fairly straightforward process that uses, in our case, managed bees such as bumblebees and honey bees to transfer powder form of a biological control agent from flower to flower. It capitalizes on characteristics of a good pollinator: they obviously fly from flower to flower and they are fuzzy allowing the biological agent and its carrier powder to stick to the body of a bee. Commonly, the biocontrol agent is a microorganism (e.g., bacteria, fungus) which is mixed with a carrier powder such as starch, and placed in a dispenser that is attached to the entrance of a hive. As the bees walk out of the hive they go through this dispenser collecting the powder on their hairs, and as they fly from flower to flower the powder containing the biocontrol agent is deposited on flowers they visit as they collect pollen and nectar. Once the bees comes back to the hive they reenter the hive through a different entrance so the biocontrol is not wasted. This actually opens up another application possibility where the returning bees could walk through another dispenser containing, for example, a biocontrol agent for Varroa mite control. I hope you now understand why I am so excited about this technology which has actually been around for a while and has been used fairly successfully in other crops (e.g., strawberries, apples, tomatoes, sunflowers, canola) for control of both pathogen and insect pests.
A few years ago I had an opportunity to witness this process in action. In 2019 I attended an apivectoring workshop in Serbia hosted at the University of Belgrade, Faculty of Biology with 20 participants attending from 10 different countries. The course was co-sponsored by several organizations including the International Commission for Plant-Pollinator Relationships (ICPPR) and the special thank you goes to Dr. Ljubiša Stanisavljević from the University of Belgrade and Dr. Peter Kevan from the University of Guelph for organizing the course and bringing us together.
During the workshop we learned theory behind plant-insect interactions, different crops and crop pests where this technology has been used, as well as the history behind the development of apivectoring from experimental trials all the way to its commercial uses including choice of the biocontrol agent, dispersal, dosage, product safety and registration, etc. Several colleagues presented examples of apivectoring success in their own countries on a variety of crops including raspberries and coffee. Perhaps the most satisfying were the field days at the Institute of Field and Vegetable Crops Novi Sad NS Seme (IFVCNS) and a local raspberry farm to see the technology in action. Researchers at the IFVCNS successfully completed trials using bumblebees to control head rot in sunflowers. At the Raspberry farm we completed our own little experiment where we set up several colonies of bumblebees (Bombus terrestris from BioBest FlyingDoctor®), we tracked the bumblebees as they went around pollinating, we collected them and collected the flowers to confirm that bumblebees indeed transferred the biocontrol agent (Clonostachys rosea formulation) onto those flowers. The specimens were observed under the microscope at the Jevremovac Botanical Garden where we also had an opportunity to see their own collection of fungal specimens isolated from the garden. We also visited the Institute for Crop Protection to examine collections of crop pathogens and entomopathogens. To say the least, this was an unforgettable opportunity to learn about this fascinating technology and have a little fun as well. The group visited the Museum of Beekeeping and Wine Cellar Živanović, where we learned about their beekeeping traditions and yes we tasted their delicious wines.
Now getting back to our own project, we followed a similar process where we isolated potential novel biocontrol agents directly from various parts of almond flowers. Our team consisting of excellent post-docs and staff (Amber Crowley-Gall, Robert N. Schaeffer, Mohamed T. Nouri and Maria Crespo) successfully identified several novel and promising microbial biocontrol agents against brown rot, nine of which also had minimal to no impact on honey bee feeding behavior. If you would like to learn more please take a look at the published article found here https://apsjournals.apsnet.org/doi/full/10.1094/PDIS-03-21-0549-RE Concurrently, we collaborated with BVT (Bee vectoring Technologies) on possible dispersal of their proprietary formulation within almond orchards. If you would like to learn more about this company please visit https://www.beevt.com/ Unfortunately (or fortunately?), the weather did not cooperate with us and the overcast, cold and rainy weather reduced bee flight activity during bloom. This provided useful information on possible appropriate times for incorporating this technology within a management program for crops blooming during inclement weather and provides further information on design changes and upgrades. I still think that this method has the potential to be integrated into almond orchard IPM as an additional tool for fungal disease control, as it has been proven valuable for a number of other crops. I am excited about the potential and possibly re-visiting this line of research.
Lastly, I want to thank you, dear reader, for going on this year long journey with us and I hope that we were able to get a glimpse of what we do at UC Davis in terms of bee research and extension programming. If you are ever visiting Northern California make sure to come and visit. And of course, a big thank you to Jerry Hayes for inviting us to share our passions with you. Until next time!
Disclaimer: Mention of any company or product name does not constitute a promotion or endorsement, and it is provided purely for educational purposes.
