Battle of the Bugs
While most gardeners try to keep insects out of the garden, Horticulturist Chelsea Mahaffey invites them in – selectively, of course. “The trick is knowing which bugs are beneficial and which are harmful,” she says. Aphids, two-spotted spider mites, and mealybugs are common insects that harm plants. If they’re present and plant damage escalates, Mahaffey reaches for the phone. Through a wholesaler, she orders a variety of natural predators—mealybug destroyers, predatory wasps, and predatory mites—that provide a form of predator-prey pest management.
“It’s weird: every month, I order live [beneficial] bugs that get shipped overnight from California,” she says. They’re transported in Styrofoam containers, along with cool packs that slow the insects’ activity. As shipments arrive at Lewis Ginter, staff and volunteers strategically spread as many as 2,000 beneficial insects throughout the Conservatory. When these insects warm up and resume activity, they hunt specific prey (the harmful bugs) and either eat them or use them as their predatory host. Over time, the number of harmful bugs is reduced. The beneficial bugs have less prey, resulting in a food shortage that reduces their populations, too.
The next time there’s an influx of harmful insects—and Mahaffey says there’s always a next time—she repeats the biocontrol cycle. “We create a mini-ecosystem that works,” she says. “My plants are healthier with less pesticide use, and it’s safer for me, volunteers, and visitors. Best of all, the good bugs continue to work long after I’m done.”