Your garden is filled with friendly insects. If you get to know them, you could reduce your problems with insect pests and your need for insecticides, according to David Robson, University of Illinois Extension horticulture educator. "If you use the wrong chemicals or overuse chemicals, you're usually much tougher on the beneficial insects than on pests. In some instances, you will have more pests than if you don't spray at all," states Robson.
In fact, most of the insects in your yard are probably "good guys" that don't do any harm, and may actually feed on the bad guys. Tiny wasps comprise the largest group of beneficial garden insects. Each species of these quarter-inch wasps is "host-specific," which means they parasitize only one species of insect pest. These wasps use their stingers to lay their eggs in the bodies of adult pests or in the pests' eggs or larvae. When the wasp grubs emerge, they eat their host.
Other beneficial insects include ground beetles that feed at night on cutworms and grubs; lacewings and ladybird beetles that feed on aphids; and pirate bugs that hide in flowers and feed on small pest insects or their eggs. Many of these beetles and bugs look particularly nasty, but aren't.
Insects on a plant aren't necessarily pests. If you have the time, it's worthwhile to go out and observe the creatures. If you see one chewing on a leaf, that makes your decision easier. Otherwise, it may be a beneficial insect. Insects commonly seen in gardens are ladybird beetle larvae. Gardeners sometimes think these purple, dragon-like critters with spines/warts and big legs are pests, but if they're in your garden, they're helping you out. People may think these are causing damage to the plant when in reality they are destroying the aphid population. The worst thing you could do is go out and spray the larvae.
Some beneficial insects such as ladybird beetles and praying mantis are commercially available, but none are all-purpose cures for garden pests. If you have aphids, some of our natural occurring ladybird beetle species will catch up with them.
Companies sell beetles that are in hibernation; when they wake up in your garden, they're not likely to stick around. The first response of any hibernating creature when it wakes up is to disperse, so the beetles fly away rather than stay in your backyard.
Praying mantises are beneficial garden insects and gardeners can buy capsules with 40 to 80 praying mantis eggs that will hatch in the spring. However, this approach to garden pest control also has problems. The first problem you encounter is that the mantises are cannibalistic. They start feeding on each other as quick as anything else. Only three or four mantis may survive this mad dinner. The survivors may not stay in your garden and may not last through the winter. Praying mantis are interesting insects to have around, but don't expect them to take care of all garden pests.
For best pest control, watch for insects and check their numbers before using pesticides.
If pests are present, balance the damage they do with the effort needed to control them.
Source:
David Robson
University of Illinois Extension Horticulture Educator
