Beneficial Insects and Other “Bugs”

Adult Lady Bug

Lady Bug Larvae

Now that the weather is warming up a bit, you may start to notice a few more “bugs” showing up in your landscape or garden. But, do you know which of these bugs are actually bad, and which ones are beneficial?

Insects and other creatures can be a desirable part of the landscape and garden because they help to reduce the numbers of plant damaging pests. Some of them are predators, while others might be parasites. Sometimes, we might recognize the adult insect, but are unaware that there is a larval stage, or what the larval stage looks like – this is certainly the case with lady bugs.

We all know what a lady bug looks like – red, sometimes yellow, with or without black spots. They eat lots of aphids and other small soft-bodied insects. But, did you know that their larvae are even more ravenous? Do you even know what they look like? Lady bug larvae are small, maybe up to about a half-inch in length, “alligator-shaped,” and black with orange spots.

Another common beneficial insect is the green lacewing. They are very delicate, light green insects with rather large lacey-looking wings. Their tiny whitish eggs are laid singly on the end of a hair-like filament, and can be found on leaves. I commonly find them in my apple trees. The very hungry larval stage resembles a tiny alligator and is usually a pale color with darkish markings.

Praying mantids are another somewhat helpful insect. They are usually two to four inches long at maturity and are usually yellowish, green or brown. Their front legs fold in a “prayer-like” manner. The immature mantids look like tiny versions of the adult. They will eat any insect that may cross their path, even the good ones, which is why they are only somewhat helpful.

Spiders, although creepy to many people, are also beneficial because of all the insects they snare in their webs. Of course, we don’t want to keep the dangerous spiders such as the Black Widow or Brown Recluse in our gardens, but if you determine that the spiders you see are harmless to people and pets, keep them around for insect control.

There are numerous beneficial “bugs” in the garden that help pollinate such as bees and hoverflies. Hoverflies, which resemble bees, are often seen hovering or nectaring at flowers – the adults feed mainly on nectar and pollen, while the larvae eat a wide range of foods. Depending on the species, the larvae may eat decaying plant and animal matter in the soil or in ponds and streams. Or they prey on aphids, thrips, and other plant-sucking insects.

Other beneficial insects are parasitic, mainly tiny wasps or flies that lay eggs either in or on specific host insects. The eggs hatch and as the larvae develop, they consume their hosts.

If you don’t have these beneficial creatures in your yard naturally, they can be purchased at nurseries and through garden catalogs, and then released according to the package directions.

There are a number of books on insects that might help you to identify the different damaging and beneficial species. Among my favorites are “Natural Enemies Handbook: The Illustrated Guide to Biological Pest Control” by Mary Louise Flint and Steve H. Dreistadt; “IPM for Gardeners: A Guide to Integrated Pest Management” by Raymond A. Cloyd, Philip L. Nixon and Nancy R. Pataky; and “Garden Insects of North America” by Whitney Cranshaw. Each of these can be purchased/ordered through local bookstores or at amazon.com.

A great website to help identify beneficial "bugs" is  http://ipm.ucdavis.edu/PMG/NE/index.html