by Courtney Llewellyn
At this year’s virtual Empire State Producers Expo, John Sanderson, associate professor of entomology at Cornell University, presented “Some Best Practices for Biocontrol Success,” which he said are “good for pretty much anything you grow in the greenhouse.”
“But biocontrol is not a silver bullet by any means all by itself,” he said. “It must be integrated into a total IPM program” – which includes monitoring, scouting, sanitation, weed management, insect exclusion and growing resistant cultivars/varieties. There will be times growers will need pesticides compatible with their biocontrols, especially if there’s a noticeable number of pests.
Biocontrols almost always must be used preventatively, as they can rarely control an already serious infestation. Biocontrol agents (BCAs) are used more often to keep a low level of pests from increasing, according to Sanderson. They are not a “fast-acting” solution.
Growers, however, need to act quickly when utilizing BCAs. “These are living animals that need to be taken care of,” Sanderson said. “They can cook, they can freeze if no one knows they’re there. It’s important you know what to do with them when they arrive.” As soon as a package arrives, check the temperature of the box interior – it should be cool but not cold. A moldy smell is a bad sign; it could mean there was too much condensation. Many BCAs need to be released the day they arrive, but storage depends on the species (predatory mites do not store well; nematodes can be stored for longer periods as long as the package isn’t opened). Make sure to check the user instructions for all species.
Other tips include avoiding storing BCAs in hot rooms or direct sunlight, even if they’re still in the shipping box. Do not store them in air conditioned offices, coolers or refrigerators because of the dry air. Always keep bottles horizontal, not vertical – bottles are shipped on their sides. Icons on labels will describe how to apply, what temperatures to apply them in, how to store them, etc.
Growers can follow the instructions at appliedbio-nomics.com/wp-content/uploads/170-quality.pdf for a basic guide on shipment survival and a quality check. For example, with predatory mites, users will want to shake out a little bit of the bottle and look for fast-running mites with a hand lens. For parasitic wasps, set aside a small sample that includes some mummies in a transparent, escape-proof container, placed in the shade at room temperature. Wasps should be visible and moving in the container after one to five days.
There are several different ways to disperse the BCAs throughout a greenhouse – placing sachets on hangers inside the canopy or on stakes beneath the canopy (but never touching the soil, where they may get wet), or broadcasting them via a hopper and a leafblower or by hand.
BCA users can also release the beneficial bugs using release cups or boxes (small containers which can be easily placed in the crop). Growers can make their own (Sanderson said Dixie cups work just fine). Using the release cups avoids having to scatter the BCAs directly into a crop, where they could fall off foliage.