URBANA – Although many insects cause damage to plant and flower gardens, a University of Illinois Extension horticulture educator suggests that some, such as damsel bugs (Nabis spp.), are so beneficial that she recommends efforts to attract them to the garden.
“When I inspect a garden for pests, I frequently find on a flowering tobacco plant small, slender, dainty damsel bugs feeding on aphids,” Kelly Allsup said. “I’ve also seen them feeding on squash-bug eggs that were laid on snapdragons and cucumbers.”
Allsup suggests attracting damsel bugs and other beneficial insects by planting a collection of plants used to produce pollen and nectar for beneficial insects to feed on or plants that host the garden pests eaten by beneficial insects called an insectary.
“Herbs such as dill, fennel, lavender, coriander, or chamomile should be planted to attract damsel bugs for shelter and food,” Allsup said. “The native purple prairie clover (Petalostemum purpureum) may also provide the damsel bugs with a host of garden pests.”
Damsel bugs have a long beak they hold under their bodies and front legs. They use their front legs to grab their prey and then their beaks to pierce and suck juices from aphids, small caterpillars, leaf hoppers, thrips, beetle larvae, insect eggs, and some beneficial insects. Most can be found in sunny locations of the garden from mid-June to mid-August. Damsel bugs overwinter in vegetation and lay their eggs in plant tissue. The nymphs look like the adults but do not have wings. Nymphs and adults prey on garden pests. Birds attracted to the garden will feed on the damsel bugs.
Allsup cautions to always inspect plants for beneficial insects before spraying pesticides because they will be killed by the application.
“Organic pesticides can cause mortality of beneficial insects,” Allsup said. “However, organic chemicals will not prevent the return of beneficial insects to the garden indefinitely. Common garden pesticides like carbamyl may prevent their return for the rest of the growing season,” she said.
For more information, visit Allsup’s blog, Flowers, Fruits and Frass, at http://web.extension.illinois.edu/lmw/eb255/.