Researchers Look For Safe Ways to Halt Invaders
By: Lesley Evans Ogden
Ever turned your nose up at discovering moldy strawberries in the container you just purchased? It is a common problem and the bane of many berry growers. In strawberries, gray mold can be caused by Botrytis cinerea, a fruit rot disease found in blueberries and raspberries too. Spores of this mold are widespread in the environment. In fields, farmers can treat it chemically with a dozen different pesticides, including pyraclostrobin, fenhexamid, and iprodione. But B. cinerea has evolved resistance to almost every chemical thrown at it. Soon, though, strawberry farmers may have help from some tiny new friends and their living delivery vehicle: a bee.
Like putting a parcel on a bus already heading to the same destination, bees are being harnessed as delivery systems for tiny microbes in a newly licensed biological control system. Bees are evolutionarily programmed to focus on flowers, part of the plant that pests often target too. Harnessing this proclivity, Bee Vectoring Technology (BVT) obtained US Environmental Protection Agency (EPA) approval in August 2019 for the fungus strain Clonostachys rosea CR-7 delivery by bees. This first-ever EPA approval for application of a plant protection product by bees is a new take on an ancient idea: biological control.
Biological control, or biocontrol, refers to suppressing pests and weeds by harnessing living organisms or viruses. In nature, biological control—mediated through such interactions as herbivory, predation, parasitism, disease, and competition—limits population sizes within functioning ecosystems. In an applied sense, biocontrol refers to human manipulation of organismal interactions for pest, weed, and disease control. Harnessed for the purposes of agriculture, forestry, conservation, and land management, it is a practice that can yield benefits and risks. But biocontrol has changed significantly since its early, largely unregulated days. As a research field, it continues to advance.
Gray mold, caused by Botrytis cinerea, is a common problem on strawberries and other fruit. Photograph: Ninjatacoshell.
A new biocontrol, Bee Vectoring Technology, was recently approved by the Environmental Protection Agency. Bees deliver a fungus strain to knock out the mold-causing pest. Here, a bumblebee walks through a plastic tray, called a vectorpak, that contains the biological active ingredient and a powder that absorbs moisture, allowing the product to stick to the bee’s legs. Photograph: Ian Collinson, Bee Vectoring Technology.