| By Jay White
Contributing Writer |
Would you think I had gone completely crazy if I said that one of the best ways to decrease the number of bugs in your garden was to increase the number of bugs in your garden? I know that sounds odd, but there really is some truth in it. I once read a statistic that said as many as 97 percent of the bugs we encounter in the garden are either beneficial to the garden or innocuous. If we learn to work with the 97 percent of good bugs that pass through our gardens, then the problems caused by the other 3 percent will be a lot easier to manage.
Beneficial bugs help gardens in many different ways and they come in all shapes and sizes. Some of them benefit us when they are infants and others when they are mature. Some fly, some crawl, some burrow and one even glows. While some eat harmful bugs, others aerate our soil and turn the garden’s waste into compost. All in all, beneficial bugs can be broken into four categories based on how they help us in the garden.
PREDATORS
Predators are animals that hunt, kill and eat other animals. Our gardens are full of predatory insects. In fact, some of the most beloved insects of all time fall into this category. Ladybugs, praying mantises and lightning bugs are all predators that love to eat many of the things that bug us in the garden.
Ladybugs. Ladybugs (or lady beetles, as they are properly classified) are by far the most beloved bug in the garden. People are often surprised when they learn that these cute and colorful little beetles are killing machines. Ladybugs are equipped with very powerful mouth structures that allow them to feast on a variety of aphids and other scale insects. Ladybugs are predatory in both their immature and adult forms. Females lay their eggs in close proximity to an aphid infestation. Once the egg hatches, the immature form begins to consume as many aphids as it can catch. If aphids are scarce, but mealybugs are plentiful, the immature form of the beetle will excrete and cover itself in wax filaments that make it look almost exactly like the mealybugs it is feasting on.
Immature ladybugs are not nearly as cute as their adult form. Many say they look like little red-and-black alligators. In fact, before I knew what they were, I actually squished them. However, because they are great at ridding you of your aphid problems, it is a very good idea to learn to identify them.
Lacewings. Green lacewings are another common predator in the Texas garden. While mature lacewings do feed on aphids and mites, they primarily feed on nectar, pollen and honeydew. The immature forms of lacewings are the real predators that you want to foster in your garden. Except for their color (dark olive or brown with yellow stripes down both sides), the immature forms look a lot like the immature form of the ladybug. Baby lacewings are commonly called “aphid lions.” These “aphid lions” will eat anything (including each other) that is soft enough for their mandibles to penetrate. Some of their common food sources are aphids, mites, mealybugs, any insect egg they can find and small caterpillars.
Praying mantises. Even though they are not nearly as cute as ladybugs, praying mantises are loved by gardeners and kids all over the world. I have yet to meet a child that does not want to hold one (once of course you have held it and reassured them that it is OK). Praying mantises are ambush killers that will sit for hours and wait for their prey to come to them. When young, they eat primarily the same thing as ladybugs and lacewings. However, as they mature, they will eat anything, and I do mean anything, they can catch. I have seen a large mantis sit on our hummingbird feeder and try to catch the hummers as they fed. Because of this unrestrained predation, praying mantises are kind of a good-news/bad-news bug for the garden. While it is true they will eat a lot of pests, they will also eat a lot of the other beneficial insects that are helping you control your other bug problems.
Lightning bugs (fireflies). Nothing typifies summer nights in Texas better than a bunch of kids chasing lightning bugs. If you are the gardening parents of those kids, you need to make sure they don’t catch all of them. While adult lightning bugs feed primarily on pollen and nectar, their larvae are specialized predators that feed on the larvae of other bugs, snails and slugs. If you are ever in your garden in the evening and the soil appears to be glowing, know that you are the proud host of firefly larvae that glow just like their parents.
PARASITES
A parasite is an organism that survives by infecting and feeding on another organism. Lucky for us, there are many parasitic insects in our garden that infest and kill many of the pests that bug our plants.
Nematodes. There are two kinds of nematodes in the garden. One type attacks the roots of your tomato plants. Those are bad. However, there is a whole other class of nematodes out there that are very good. Nematodes are microscopic “bugs” that live in the soil. They are one of the most common animals on earth and they have been around for millions of years. Predatory nematodes live in the moist soil around the root zone of your plants. There, they seek out and destroy the larval forms of more than 250 pests. Some of the ones we care about are thrips, fleas, ticks, chiggers, chinch bugs, cucumber beetles, cutworms, loopers, peach tree borers, stinkbugs and grubs.
Parasitic wasps. Parasitic wasps are generally pretty small. Because of this, they often go unnoticed. However, whether you see them there or not, you want them in your garden. The parasitic wasps we have here in Texas are generally small, dark-colored, flying bugs that attack things like aphids and hornworms. The female lays her egg in the host and as the larva grows it eats its way out of the host. One form of wasp specifically attacks aphids. As the insect matures inside the aphid, the aphid begins to change from an almost clear or milky color to brown. When mature, the baby wasp chews a hole in the abdomen of the host and then flies away. Aphids hosting wasp larvae are called “aphid zombies.”
Another type of wasp attacks hornworms and other caterpillars. While we often miss the adult wasp, it is very easy to see their effects on these caterpillars. If you find a caterpillar in your garden that has many white specks or bumps on its back, leave it alone. Those white bumps are the eggs of the wasp. Once hatched, the larvae will bore their way inside the caterpillar. Once inside they will grow and eat until they chew their way out. This kills the caterpillar and releases several more hunters into your garden.
POLLINATORS
Pollination is the process of transferring pollen from the male parts of the plant to the female parts. Fertilization will not occur without pollination. A full 90 percent of the plants on earth use insects to assist in the pollination process.
Bees. Bees and gardens go together like hands and gloves. Because of all of the work they do pollinating our crops, it is hard to think of one without the other. This is one reason the recent decline in their numbers is getting so much press. While a population decline in this very important pollinator is disappointing to hobbyists, it is an economic disaster to those who rely on bees to pollinate the crops they grow commercially.
If you look closely, you will find three different types of bees in your garden. The first are what are commonly called “honeybees.” Honeybees are the relatively friendly bee that we all love to observe in our garden. This group of bees is not native to the Americas. Most of what we think of as “bees” were brought here by European settlers as early as the 1600s. Back in those days, bees were primarily valued for their honey production. American Indians dreaded the appearance of these bees because they soon realized that the appearance of “white men’s flies” meant that white settlers were not far behind.
Native bees in Texas are smaller, less colorful and much less social than European honeybees. While still responsible for a significant amount of pollination, these bees travel alone. If you see something that looks like a honeybee, but is smaller and oddly colored, it is probably a native bee. Native bees have not been studied like the honeybee. However, the people who do study them believe their numbers are falling too. While they believe that disease and pesticide issues cause some of the decline, researchers feel that loss of habitat is their biggest enemy. If you want to look for native bee species, do your observation in wildflower fields. Many of these bees prefer the nectar of all of those native flowers we all love so much.
Bumblebees also do a whole lot of pollinating for gardeners. While I realize that honeybees are doing most of the heavy lifting in my rows and borders, it is the appearance of their oversized cousins that makes me run for the camera. Texas has nine species of native bumblebees. Like all other types of bees, bumblebee populations are beginning to dwindle. The Texas Parks and Wildlife department has set up a great website to help you learn more about our bumblebees (http://texasbumblebees.com/). They also have a Facebook page. These sites were set up to educate the public and gather information on bumblebee populations. This year, when you see bumblebees in your garden, take a minute to log your sightings on one of these websites. Your information will help them determine populations and ranges, and hopefully acquire some grant money to protect and further study them.
Butterflies and moths. Adult butterflies and moths are great little pollinators; unfortunately their offspring are responsible for some of the biggest pests in the garden. Swallowtail butterfly larvae will munch away on our dill, but most of us can bear that. What we can’t bear are the effects of hornworms, cabbage loopers and cutworms. Each of these destructive pests is the offspring of several moths that commonly appear in our gardens.
Wasps. In Texas, we are familiar with red wasps and yellow jackets. Since both of them can and will sting, they often get a bad rap. Despite their reputation, wasps perform two valuable functions for gardeners. The first is pollination. Adult wasps feed primarily on nectar and honey. Just like the honeybee, their foraging results in a lot of pollen-transfer. In addition to their pollination role, wasps are also predators. They kill many bugs, larvae and caterpillars to feed to their young. Dirt daubers (or mud daubers) are another wasp that eats pollen and nectar and transfers pollen. However, what makes them kind of special to me is what they feed their offspring — baby black and brown widow spiders! While they kill and eat several other varieties of spider, the fact that they eat black widows makes me willing to tolerate the numerous mud nests that they leave all over my garage.
Hoverflies. Hoverflies (or seraphid flies) are a specialized group of flies that hover over flowers to feed on nectar. But they also crawl around on flowers to get at the pollen. Because they have no defenses of their own, hoverflies have evolved to look a lot like little honeybees. These guys are small and fast; so you have to look close to see them. If you do see one, it is a good thing. Not only do they pollinate your flowers, they also produce offspring that feed on aphids.
DECOMPOSERS
Not all of the beneficial bugs in our gardens eat bad bugs or pollinate flowers. Some work very hard to aerate our soil and fertilize our plants.
Lovebugs. I hate lovebugs. Each year I drive through herds of them and then spend countless hours cleaning them off my grill and windshield. When lovebugs are not loving each other, they can be found sipping nectar and eating pollen. However, their real service to gardens happens after they lay their eggs. Lovebugs lay their eggs in dry grass or dead leaves. When they hatch, they eat all of that organic material and convert it into the nutrient rich humus that is such a benefit to our plants.
Roly polies. Whether you call them roly polies or pill bugs, these hard-shelled critters are good for a whole lot more than entertaining the grandkids. Roly polies, a terrestrial crustacean, are members of the woodlice family. As such they are able to break down the tough cellulose of decaying trees and shrubs. Pill bugs require low light and high moisture to thrive. Because of this, roly polies do very well in a well mulched garden.
Earthworms. While not technically a bug or an insect, earthworms do so much good in the garden that I have to include them. Earthworms improve our garden in so many ways. They dig tunnels that allow air, water and nutrients to move through the soil. They turn large pieces of dead organic matter into nutrient rich humus and distribute it in all layers of soil. Then, they excrete “castings” which have five times more nitrogen, seven times more phosphorous and eleven times more potassium than the soil in which they live.
Scientists estimate there are more than 1 million earthworms in each acre of healthy soil. If you want to encourage more earthworms to take up residence in your garden, keep the soil moist and provide lots of dead organic matter to feed on. If you have access to dry leaves, use them as mulch. They will keep down your weeds and your earthworms will love you.
Gardeners have been fighting “The Battle of the Bugs” for as long as there have been gardens. We haven’t won it yet and I firmly believe we never will. We can spray them, we can trap them and we can squish them, but they always return. While I am not naive enough to believe that we can eradicate all of the bad bugs in the garden by encouraging the good ones, I do believe we can keep damage down to an acceptable level by working with nature. So this year, before you pull out the dust and the sprays to kill 3 percent of the bugs in your garden, remember the other 97 percent that are working very hard to help you get rid of the bad guys, pollinate your flowers and condition your soil.
