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The Good, the Bad and the Ugly Bugs continued

Are those good bugs or bad bugs lurking in your garden? Before you spray, find out if that creepy-looking bug is really a hazard to your garden.

© USDA/Q. Holdman

In this article ...

Page 1
  • The Rogue's Gallery 
  • Centipedes and Millipedes
  • Integrated Pest Management 
  • Flying Stingers
  • Worms: Green, Brown and Invisible   

Page 2

Soil-dwelling grubs, which are mostly white with obvious legs and heads, usually aren’t good news, as they feed on plant roots and crawl to the soil surface at night, where they gnaw on plants. Some of these can be very detrimental to your plants, like the cutworm that chews off plants at ground level—even one of these grubs is undesirable in the garden. Grubs are usually exposed during cultivation or debris removal; some gardeners choose to put the grubs they find in the birdfeeder as a tasty treat for their feathered friends. 

Grasshoppers, Katydids and Crickets
These big-legged, winged monsters are more of a moral dilemma than a gardening question. Should one kill grasshoppers and katydids in the garden? Perhaps not. Grasshoppers can eat a bunch of plant flesh when they’re hungry, but these hoppers are usually vagrants just passing through the garden; a healthy, local bird population should take care of any hoppers.

Smaller crickets are permanent residents in the garden, but they’re omnivores and won’t do much damage beyond cutting down seedlings when there’s nothing more desirable to eat. Crickets can chew through a lot of debris and their part in the breakdown of organic refuse is important to a natural soil system.


Lacewings and Preying Mantids
Preying mantids and their smaller cousins, the lacewings, may look like little monsters, but they’re definitely favorable in a garden. Most seasoned gardeners understand the benefits of preying mantids and take measures to protect any mantis egg clusters they find in their garden; however, fewer gardeners are familiar with lacewings. Lacewing adults appear to have wings that are much bigger than their bodies.

The larvae crawl around and prey on anything they can get a hold of, particularly aphids and mites. Finding lacewings or their tiny egg cases, which look like fungal spore sacs, is a happy moment for any gardener. Both lacewings and preying mantids are frequently sold by biological control companies.


Beetles are a strange group. One could generalize and say that small- to medium-sized beetles are probably detrimental, and that larger beetles are most likely valuable predators. It’s the same old story: The bad beetles eat plants. Squash bugs and Diabrotica are common pestiferous beetles on soft-bodied plants. Bark beetles and their larvae tunnel under the bark of cedars and other conifers. One or two of these munchers isn’t so bad, but when they arrive en mass, they can be devastating, potentially killing the trees.  

Buying Bugs  

Buying beneficial bugs has come a long way since the 1970s, when harvested masses of tired, adult ladybugs were sold, sometimes door to door, to gullible gardeners. These days the range of beneficials has exploded, and the cultivation and shipping practices have evolved to the point that transportation losses are rare. Many interesting sites now sell beneficial insects online:

Buglogical Control Systems


Planet Natural


The best-known good beetles are ladybugs, but there’s also a slew of other good beetles, like the Carabidae, which look like shiny, green jewels—all of these beetles eat plant pests. The European ground beetle can be medium- to large-sized; black, green or purple in color; and they like to live among plant debris, from which they venture forth to seek out caterpillars and other soft-bodied prey. These predatory beetles are definitely high on a gardener’s list of good friends.


The True Bugs: Aphids, Whiteflies, Mealybugs and Scale
As it turns out, those insects that are “true bugs” in the scientific sense are almost all pests. This list of undesirable characters includes bedbugs, aphids, whiteflies, plant lice, mealybugs and scale. The unusual exception here is the assassin bug (Reduviidae), which is an effective predator.

Spring growth on rose bushes is likely to attract hordes of aphids. Their cohorts, whiteflies and plant lice, are even worse pests because they not only suck juices from tender growing parts, they also often transmit diseases from one plant to another. Because they multiply rapidly, infestations of these pests are quite possible on most types of cultivated plants.  

Whiteflies are the cute, tiny, bright-white moths that tend to converge on greenhouses. Plant lice are tiny bugs that look like a toy-sized earwig. Aphids come in a rainbow of colors and they breed like rabbits, quickly filling a nice grazing opportunity.

Mealybugs and scale adore citrus and similar hardwood shrubs. One has to look for these fiends, as they’re usually slightly hidden in branch joints or underneath the foliage. Mealybugs look like little flecks of cotton and scale look like little bits of dried glue. Cottony, cushiony scale also look like a bit of white fluff. Once you see either of these two, there are usually more of them already installed on the plant. The appearance of an infestation of scale or mealybugs probably indicates a lack of predatory  insects; plants that are fed a high-nitrogen diet are also more susceptible to infestations. While many beneficial insects available will eat scale and mealybugs, releasing beneficials after the infestation is not likely to solve the problem quickly. Home gardeners with only a few plants can hand-pick the pests, but farmers usually resort to oil sprays. 


Moths and Butterflies
Butterflies and moths might look nice fluttering about, but too many fliers indicate a potential problem. The big, regal-looking butterflies, like the monarchs and swallowtails, are unlikely to lay many eggs in your garden, but the pastel Cabbage Butterfly, the huge Five-spotted Hawkmoth and the little grayish-brown moth known as the codling moth can all signal possible problems in the way of cabbage worms, tomato hookworms, and apple worms. In their favor, butterflies feed on nectar and pollinate flowers in their quest for food.


Spiders have a bad rap because people get bitten now and again. We spend millions of dollars on questionable spider sprayings to little effect because spiders are extremely widespread and always looking for new areas to inhabit. A sprayed area just means that there are no spiders left to compete in that area. If spiders want to live in your house or your garden, there’s really not much that can be done besides regular cleaning of nesting areas.

The good news is that spiders are always valuable helpers in the garden. Some spiders target specific prey, while others attack a range of different insects. Having a healthy spider population in a garden adds a strong line of defense against pestiferous insects; because they are actively cannibalistic, having a resident group of spiders is also the best defense against any spider population explosions. (A great spider information site is www.washington.edu/burkemuseum/spidermyth/index.html)

Gardens aren’t planned; they evolve and self-confidence among bugs is similarly evolved, not acquired all at once. Here’s an exercise: Try to look a bit more closely at the bugs you see in your garden and do some studying. Get some magazines and books or go online and learn a bit more about the real dangers and benefits of bugs in your garden. Perhaps the next time a wasp flies into your hair, you’ll calmly wonder if it’s perhaps an Ichneumon, instead of jumping up, screaming and knocking over the punch bowl.

About the Author: Rick Gush is a freelance writer based in Italy. 

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The Good, the Bad and the Ugly Bugs continued

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Reader Comments
Enjoyed the reading but would love to see more photos of the bad worms. We have small blackish worms on our tomatoe leaves and now the leaves are pretty and lacey. My tomatoes are large but still green.

Also, does chipped cedar help or hurt the soil, good vs bad bugs, butterflies etc.
Kathleen, Houston, TX
Posted: 5/15/2012 8:54:34 AM
exceptionately well done, thank you ....
ron, tiverton, RI
Posted: 6/16/2010 7:04:53 PM
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