Growing plants to attract insect predators
May 22, 2013
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URBANA – As gardeners trend toward more natural ways to grow small fruits and vegetables, both in the backyard and at community garden plots where traditional control products may not be allowed, insect predators can be of use, said University of Illinois Extension horticulture educator Richard Hentschel.

“There are a number of predator insects that can help us control the destructive ones,” said Hentschel. “The commonly known ones include several versions of the lady beetle. Both the adults and larvae feed on aphids. Ground beetles also feed on both adults and larvae of destructive insects such as root maggots, snails, slugs, caterpillars, and weed seeds.

“Other lesser known predators are pirate bugs, damsel bug nymphs, and assassin bugs,” he added. “These three feed on soft bodied insects that damage our plants. Lacewing larvae feed mainly on aphids mainly whereas the adults also use nectar and pollen as food besides feeding on aphids.” 

Another group of predators, not officially an insect, but an insect relative, includes spiders. All spiders do not necessarily build a typical web, Hentschel said. Those are the orb weavers, catching their prey in the web itself.

Other spiders include wolf spiders, preying on insects that move along the ground. Also included are jumping spiders, who get their name by how they attack their prey. These spiders stalk and then pounce on prey.  Crab spiders will usually sit quietly waiting for prey to walk by and then reach out with their strong legs and make the capture. They can walk sideways and resemble crabs in that way, Hentschel explained.

“Spiders can be found throughout the backyard and in undisturbed areas,” he said. “They do not necessarily need a favored plant but a favorable environment.”

According to Hentschel, another insect that is often referred to, but is not as helpful, is the praying mantis. “This is a very interesting insect to watch, yet is not one of the better predators for the garden.”  

Although predator insects, such as the lady beetle, can be purchased by mail ordrepared to apply a timely rescue treatment,” he said.

Gray added that to date, there is no evidence of field-level resistance development by European corn borers to Bt hybrids.

“This is a remarkable success story nearly 20 years after the commercial release (1996) of Bt hybrids aimed at this insect,” Gray said.