Pest control is a delicate balancing act

6/12/2018

Bugs. Their segmented bodies and weird eyes make it seem as if they have come from another world. They creep and crawl. They sting. They ruin picnics and invade your pantry.

They are crawling all over your garden, feasting on your tomatoes and your roses.

How can we get rid of them?

You can’t, and you don’t want to, said Mitch Magdich, curator of education at the Toledo Zoo.

“Of the overall number of insects worldwide, the ones that are actually harmful is a very very low percentage of the total number of species,” Mr. Magdich said. “Insects do a lot more good than harm. But it’s the harmful ones that get the press.”

Some insects are misunderstood.

That dangerous looking bee?

“When they’re in the garden they’re not interested in stinging you,” Mr. Magich said.

Bees are among the myriad species of pollinators, along with ladybugs, pollen wasps, ants, flies, including bee flies, hoverflies and mosquitoes; lepidopterans, both butterflies and moths, and flower beetles.

“Any of those critters you want to see,” Mr. Magdich said, “because plants can’t produce seed without pollinators. Fruits, vegetables, melons, squashes rely upon the ecological pollinators, bees of some type.”

Yes, wasps and bees can sting, but not while they’re going about their business, Mr. Magdich said.

“When that bee goes over to your garden and forages for pollen and nectar they’re not going to bother you,” he said. “Leave them alone and you’ll be fine.”

He agrees that ants shouldn’t raid your pantry, but leave them alone when they’re outside.

Ants’ biomass surpasses all the vertebrates on the earth.

“Out in nature, they provide ecological services; they aerate the soil, they carry seeds, they plant seeds,” Mr. Magdich said.

And that dainty ladybug? The insect popular with nursery rhymers is a pretty lethal little insect when it comes to pests.

“They are a good biological control of those pest insects we don’t want out on our garden plants,” he said. They are particularly effective at controlling aphids, the bane of many a rose gardener.

Even flies and wasps have other purposes than just to bother us, he said. They are parasitoids, some of the hundreds of thousands of species of insects that lay eggs on arthropods, which not only includes other insects such as mites, spiders, centipedes, millipedes, lobsters, and crabs.

These parasitoids, Mr. Magdich said, lay eggs on the larva and caterpillars. These eggs hatch and eat away at the caterpillar, in a zombie-apocalypse kind of action, he said, a good control for pests like the sphinx moth, which, in its caterpillar stage, is the tomato hornworm that is especially attracted to tomato plants, or the tobacco hornworm, which hungers for tobacco.

Many people are creeped out by spiders, but seasoned gardeners will invite them in.

Spiders are pretty important, Mr. Magdich said, because they control pests, especially late in the season. And the praying mantis is another guardian of the garden, a predatory insect known for its alienlike appearance and its toughness and effectiveness in controlling pests.

But not every bug or beetle, no matter how important they are to the biological scheme of things, is welcome in the garden or your lawn.

In its larval stage the beetle, called grubs at this point, will attack your lawn and feast on the roots, killing large patches. These grubs mature, which of course leads to more grubs and more problems.

An invasive species, the Japanese beetle is among the most pervasive, and, similar to other invasive species like the emerald ash borer, it has no natural predator in North America.

The ash borer devastated the ash tree population of northwest Ohio at its heyday, and while many assume that the crisis is over, Mr. Magdich said that isn’t the case.

“Eradication is off the plate,” he said. “It’s kind of leveling out. They had really aggressive programs here in northwest Ohio, but it came to nothing because it started spreading anyway.”

Not much can be done to control a species without a natural predator, he said. While disease occurs in such a large population, it is cyclical and more often than not does not eradicate the problem.

The gypsy moth is another invasive species that can “wreak havoc on the environment,” he said, causing a mess with its excrement and deforesting large swaths of land.

The box elder, however, is a native insect that not only feeds off box elder and maple trees but can also damage flowers and creep into buildings.

Stink bugs and shield bugs are damaging to agriculture as well as ornamental plants.

Add in corn borers and cabbage white butterfly, there’s a whole host of pests gardeners are battling.

The problem with getting rid of these pests is how do you do that without killing the spiders and the bees and the praying mantids?

Unfortunately, Mr. Magdich said, you don’t.

“It’s a balancing act,” he said. “Because with the good bugs come the bad bugs, and vice versa.”

Most pesticides don’t just target a specific bug, so the beneficial ones are collateral damage.

Many gardeners are turning to nonchemical pesticides and other methods, such as bug hotels, companion plants, and yes, more beneficial insects.

“You don’t want to throw the baby out with the bath water,” Mr. Magdich said.

Adding plants that will attract the pollinators and the spiders and the praying mantis will not only keep a control on those nasty pests, they will help fight the effects of climate change, which, Mr. Magdich said, is perhaps the biggest pest of all.

While one person alone can’t negate the effects of a warming planet, everyone can do his or her part to limit the amount of of carbon dioxide that’s being released into the environment.

“Climate change is going to have an impact on the bumble bees, it’s going to have a big impact on pollination and other ecological services, and it’s already playing out,” he said.

“It’s the global village sort of thing; we all have to do our part to stop the release of CO2.”

Some of the things we can do, he said, is not run the lawnmower so often. Plant bushes and other vegetation that will welcome the pollinators and entice the butterflies. Be careful of the pesticides used to control the unwanted guests in your garden.

And be kind to those bugs. We need them around.

Contact Heather Denniss at hdenniss@theblade.com