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WICHE: The unseen heroes of the garden

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I appreciate the beneficial insects that help keep the garden in balance, but there are good things at work that go unseen.

By Jeneen Wiche

Have you ever considered the nematode? I appreciate the beneficial insects that help keep the garden in balance, but there are good things at work that go unseen.

I recently released who knows how many in and around my vegetable garden in hopes that they will finally take care of my most annoying vegetable pest: the flea beetle.

I do not use chemical pesticides in my vegetable garden, so these beneficial nematodes are my last hope; and once the colony is established, they should stick around and grow in population to do more good as the season progresses (and in years to come).

Blair Leano-Helvey of Entomology Solutions (www.bugsbehavingbadly.com) explained that I must first be patient. The present generation of flea beetles will not be controlled.

Rather, the generations pupating in the soil will be lunch for the nematodes. This is where the microscopic soil-dweller parasitizes the larvae of the pest – the flea beetle, flea larvae, Japanese beetle larvae, etc.

Leano-Helvey also sent me home with some wasp cocoons that parasitize flies to release around the barn and in the sheep pastures. Having fewer flies is really appealing to me.

Many beneficials we can see, and some we love, and some we view as threats. Before you squish or spray, consider the next generation of beneficial insects that you may be eliminating from your garden. 

For instance:

  • We delight over butterflies but likely kill many while in the caterpillar stage.
  • We love lady beetles, but the nymph stage looks a little scary.
  • And we swat and spray ever fly, wasp and bee in earshot.

One of the challenges we face when it comes to beneficial insects is that we have a hard time distinguishing between the good guys and the true pests. I recommend adding a book or pamphlet to your garden library that illustrates the insects that we do want out in the garden.

Beneficial insects are considered such because they prey on garden pests at some stage of their lives. Insects look different at the different stages of development.

Larva, nymphs and adults do different things to subsist and may look dramatically different then the insects we recognize. Learn to identify them in all stages of development.

The quintessential example is the braconid wasp. You may be surprised to find that various species of braconid wasps are some of our garden’s best friends.

The tobacco hornworm is recognized by many gardeners, especially those who love to grow tomatoes. This hornworm is a large green caterpillar with chevron marks of white and black along its back. It can defoliate a tomato plant overnight.

Often we see the hornworm covered in small oval-shaped white cocoons. These are baby wasp cocoons that are feeding on the caterpillar as they develop. Not much remains of the caterpillar once the cocoons have done their thing.

The bottom line is this: Save those tobacco hornworms covered in cocoons so that you have another generation of beneficial braconid wasps in your garden.

These wasps lay their eggs on a number of other pests, as well, including the larvae of other caterpillars, beetles, aphids and flies.

Assassin bugs come in various colors, including red, black, green and brown. Their bodies are flat, thin and angular, and they prove to be voracious eaters of both the adult and larval stage of aphids, beetles, caterpillars, flies and leafhoppers.

The scarab-like ground beetle appears black and slightly iridescent and prefers to lunch on cutworms, fly eggs, maggots, slugs, snails and other soil-dwelling pests, such as cabbage root maggots and Colorado potato beetle larvae.

Lacewings and lady beetles love aphids, thrips, mites and scales, among other soft-bodied pests. And the insidious flower bug, also known as the minute pirate bug, uses its long snout to snag the nymphs of leafhoppers, mites and other small insects.

Reduce the use of pesticides, and you increase the population of beneficials. You can attract beneficials by planting certain herbs, flowers and vegetables.

Plants that produce generous amounts of nectar and pollen typically attract the good guys. Cilantro, dill and fennel pull in a great many beneficials. So do mint, borage, lavender, bee balm, Queen Ann’s lace, amaranth, yarrow, nigella and many others.