Take Advantage of the Beneficial Insects

Barbara Mrgich
Adams County Master Gardener

Everything in nature exists as a check or balance to something else. If mankind would just keep his finger out of the mix, the earth would get along just fine. But we humans keep working at messing up the balance. That is especially true when it comes to gardening and landscape. For many homeowners, their only goal is to have a perfect lawn with no bugs. Many people don’t recognize the difference between beneficial insects and pests, nor do they understand just how important those beneficial insects are to our very life.

There are different categories of beneficials, and at the top of the list is POLLINATORS. Pollinators move pollen to fertilize the egg which allows the plant to produce fruit and propagate.

Bees are, by far, the royalty of the pollinators. A huge majority of our plants would disappear if bees were not here to pollinate them. Keep in mind that if the plants were to disappear, we could not exist either. You might say, "Well, we could just eat meat", but the animals we eat exist on plants as their food source.

Besides pollinators, there are at least three other types of beneficial insects that perform important functions. Some are Predators, meaning that they hunt down and eat other insects. Among others, these include spiders, praying mantis, lady bugs, green lacewings, wasps, dragon flies, and assassin bugs.

Some insects are Parasitoids. Unlike parasites who live off their host without killing it, parasitoids kill the host. These insects actually lay their eggs inside the pest. The eggs hatch and eat the victim from the inside out. (Don’t worry - they only attack other insects, not humans.) Parasitoids include many species of tiny wasps, flies called tachinid flies, beetles, and also Gordian worms that kill crickets and grass hoppers. Between them all they kill a wide variety of garden pests.

Another type of beneficial insect is the Decomposer. Decomposers break down dead plants and animals. Decomposers are very important because, without them, dead matter and waste would just pile up. The decomposers are responsible for turning a big pile of pulled weeds and garbage into compost.

Most beneficial insects are in steep decline. We need to be very concerned about this fact. The cause of this decline is simple. It’s a combination of loss of habitat, invasive plants crowding out the natives, and over-use of pesticides. All three problems are caused by man.

Here are three quotes from a favorite expert, Dr. Michael Raupp, "The Bug Guy", from the University of Maryland:

"Plant damaging bugs are winning because we’ve largely wiped out the other bugs that would’ve controlled them."

"Frustrated by the many bugs eating your measly few plants? Your best bet isn’t to reach for the sprayer. It’s to plant more plants." (Preferably natives)

"What happens in a diverse landscape is that the population of beneficial insects goes way up, and those bugs start knocking back the pests without us even realizing it."

Dr. Doug Tallamy, from the University of Delaware, tells us that since most of the earth’s natural areas have been taken over by man, it is now up to us home gardeners to create gardens which will enable beneficial insects to endure. He has two excellent books, BRINGING NATURE HOME, and NATURE’S LAST HOPE. We should all read his books.

He adds, "If everyone started to reduce that biological wasteland known as the lawn in favor of native plants including trees, we could create one big connected habitat for species we are driving to the brink."

Growing more native plant species attracts a larger diversity of beneficial insects. Different plants attract different insects. Some of these insects are so small that we are often not aware of the important work they do for us.

Insects have very distinct life stages. You may see damage on a plant and think you have to spray something on it when, in reality, the culprit who caused the damage has already progressed to the next stage of its life and is no longer causing damage. The second scenario might be that the beneficials have already moved in and, when you spray, you will be killing them also.

Another beneficial living organism, although not an insect, is mycorrhizal fungi. A major benefit of adding compost to the soil is to encourage the growth of mycorrhizal fungi. This is a fungus that looks like long, white strings in the soil. Mycorrhizal fungus has a symbiotic relationship with your garden plant roots. It gets carbohydrates created by the plant through photosynthesis, and in return, it delivers hard to reach minerals and nutrients to the plant roots from up to 100 yards away. It is also known to support the plant through drought conditions by bringing droplets of moisture to the roots. Be aware that tilling destroys mycorrhizal fungi.

Including a variety of native plants in our garden is vital for attracting beneficial insects because, for eons, these insects have co-existed alongside those native plants. Many exotic plants (non-natives) may look the same to us, but sometimes the native insects don’t even recognize them as usable.

I am someone who grows many native plants, and has used large amounts of compost in my gardens for many years. I have not sprayed insecticides or chemicals on my property for just as long, I have few or no problems with pests or disease in my ornamental gardens. I attribute my success to the beneficial insects that come to visit.

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