Gardening with Laurie: Many bugs beneficial for gardens

March 17, 2010 at midnight
Updated March 16, 2010 at 10:17 p.m.

By Laurie Garretson

Mention bugs to most gardeners, and they immediately think of insecticides.

To many people, the only good bug is a dead bug.

The fact is, most insects are not going to cause you or your garden any harm. Most insects are beneficial. We just give so much attention to the bad ones, the ones that bother us and our plants.

As with all organic gardening, nature can, and will take care of everything, if given the chance.

Nature has several methods to keep pests in check: weather conditions, diseases and beneficial insects.

Unfortunately, at times these factors can break down, ultimately from some condition caused by man. At these times, we may need to step in and give Mother Nature a hand.

Releasing beneficial insects in your landscape can give nature a helping hand. There are two main types of beneficial insects: predators and parasitoids.

Predators will hunt for their prey and eat them, while parasitoids will seek out certain insects to lay their eggs on or in.

In early spring, many of us are usually looking for help from the parasitoids. These helpers help to control a pesky worm that's a big problem for many of us in our trees, mainly oak trees.

The oak leaf rollers or loopers can totally defoliate a young tree overnight. This loss of foliage then weakens the tree and slows its growth. In its weakened condition, the tree is also prone to diseases and other insects.

Many people tell me they totally avoid being in their yards when their trees are inhabited by these pests.

When disturbed, the worms will hang from silk threads they spin. They will drop on outdoor furniture, cars, sidewalks, pets and you. Although they are not harmful to people or pets, they are a big nuisance.

Some say because of the hundreds of worms in their trees, they actually hear the worms chewing on the foliage. I guess this wouldn't be very inviting.

One beneficial insect that will help to rid your yard of these pesky worms, as well as many other bad worms, are trichogramma wasp. The trichogramma is one of the smallest insects on the planet. They are small because nature has chosen them to parasitize other insect eggs. The trichogramma actually fully develops into adulthood inside the egg of a pest insect.

Parasitized trichogramma eggs, and other beneficial insects, are available to be released in your yard. The eggs come on a small piece of stock paper. Once attached to the trunk of a tree, the tiny wasps soon emerge from the eggs and seek out the eggs of the oak leaf worms.

The trichogramma wasp then searches for worm eggs by an odor left behind from the moth that laid them. Most moths will accidentally leave some of the scales from their wings as they lay eggs.

Once the egg is found, the trichograma then deposits one or two of her own eggs inside the developing host egg.

In a few days, the baby trichogramma hatches and consumes the egg yolk and the rest of the worm embryo. The trichogramma then completes its development and chews its way out of the egg shell.

Once its out of the egg it takes a good smell and inspects the egg that it came from. The wasps store this information to use as it searches for the next host egg. From there, the process starts all over again.

If plagued by worms or other bad insects, it may be time to call in some help from the good guys. Releasing beneficial insects periodically throughout the season can help out Mother Nature, which in turn will then help you.

Until next time, let's try to garden with nature, not against it, and maybe all our weeds will become wildflowers.

Laurie Garretson is a Victoria gardener and nursery owner. Send your gardening questions to or in care of the Advocate, P.O. Box 1518, Victoria, TX 77902.



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