Helping the Good Bugs

Friday, May 3rd, 2013 by Jenny Watts
    • Petunias can be planted now. Their bright flowers will bloom all summer in hot, sunny locations and they will take a light frost.
    • It’s time to put out oriole feeders. You can also attract them with fresh orange halves.
    • Flower seeds can be sown directly in the garden now. Cosmos, marigolds and zinnias will give you beautiful flowers all summer.
    • Feed roses to encourage a beautiful display of color later this month. Treat plants to prevent insect and disease problems.
    • Plant the vegetable garden this month, but remember that late frosts can still nip tender young plants.

Helping the Good Bugs

Not all bugs are bad bugs. In fact there are many bugs that don’t eat plants at all, they feed on other insects. By encouraging these beneficial insects, you can maintain a natural balance in your garden and reduce damage done by insect pests with a minimum of pesticide sprays.

Insects that feed on other insects are divided into two types, the predators and the parasites. Predators move around looking for plant feeders such as aphids, mites and caterpillars. Lacewing larvae and ladybug larvae and adults aggressively devour aphid populations. Ground beetles prey on a variety of ground-dwelling pests like cutworms, root maggots and slug eggs. Predatory mites attack spider mites and two-spotted mites feed on many plants and can be a real problem in hot dry weather. Beneficial nematodes attack root pests like cutworms, weevils and grubs.

Parasites are insects that develop in the bodies of other “host” insects. Most parasites are tiny wasps or flies whose larvae eat other insects from within. Tiny parasitoid wasps are aggressive beyond their size when it comes to pursuing aphids and caterpillars. They provide a very effective means of insect control.

Ladybugs, Tricho-Gramma wasps, predatory mites and beneficial nematodes can be purchased to put in your garden or greenhouse.

These various beneficial insects consume large numbers of pest insects, but their diets are not limited to other insects. In fact, many of the beneficial species have periods in their life cycles when they survive only on nectar and pollen. So by planting a variety of insect-attracting plants you can keep beneficial insects going strong.

There are two plant groups that are particularly attractive to beneficial insects. They are the parsley or carrot family and the daisy or sunflower family. Most beneficial insects have short mouthparts and cannot reach far into a flower for nectar and pollen. The small flowers on these plants put pollen and nectar within reach of these tiny insects.

The carrot family includes many herbs such as anise, dill, fennel, and cilantro and vegetables such as carrots, parsley and celery. The flowers of these plants are arranged in clusters called umbels which are shaped like an umbrella. They produce large amounts of nectar as well as shelter for insect-feeding insects, another critical requirement. To take advantage of their nectar, you just let a few of your carrot, parsley and celery plants go to seed.

The sunflower family is the largest family of flowers on the planet. These “flowers” are actually made up of dozens or hundreds of tiny flowers clustered together. This family includes yarrows, marigolds, zinnias, asters, calendulas, chrysanthemums, cosmos and many more. While these plants have less nectar than those of the parsley family, the flowers last a long time, and with planning, you can have some in bloom throughout the growing season.

Alyssum, borage, statice, various clovers and yarrows also attract parasitoid and predatory insects. Low-growing plants, such as thyme, rosemary, or mint, provide shelter for ground beetles and other beneficial insects.

Get to know what the good bugs look like and lure them to your garden by growing these attractive flowers. In a few years, you may find that you just don’t need insecticides any more.

It’s a Bug-Eat-Bug World

Wednesday, September 15th, 2010 by Jenny Watts
    • Cool season vegetables should be planted right away to insure good crops this fall.
    • Pansies and snapdragons can be planted now to replace long, leggy annuals. They will give you color this fall, winter and next spring.
    • First-year fruit trees need to be well-watered through the dry weather. If they are neglected the first year, they may never be strong, productive trees.
    • Lilac bushes will bloom better next spring if you cut back on the watering now.

It’s a Bug-Eat-Bug World

Although insects are the main consumers of plants on Earth, many insects survive by living off other insects. They do this by acting as predators, parasitoids or pathogens.

Lady beetles, commonly known as ladybugs, are well-known examples of predatory insects. They are especially attracted to plant nectar and nectar-eating pests, such as aphids, mites, thrips and mealybugs. Adult ladybugs eat mostly aphids, but their larvae eat insect eggs, beetle larvae, aphids and other soft-bodied insects. To encourage ladybugs to stay in your garden, plant a variety of flowering plants including daisies.

The Green Lacewing larva is a voracious predator of many soft-bodied insect pests. When their eggs hatch, the larvae, which are about ⅛” long, look like tiny alligators. Known as the “Aphid Lions”, each larva can eat up to 1,000 aphids per day. Lacewing larvae feed on many different pest insects. In general, they attack the eggs and the immature stages of most soft-bodied pests such as: aphids, thrips, spider mites, sweet potato & greenhouse whitefly, mealybugs, leafhoppers, and the eggs and caterpillars of most pest moths.

Predatory Mites are a very effective defense against spider mites. Each predatory mite will consume about 7 adult mites, 20 juveniles or 25 eggs per day. Once released, they will immediately begin searching for food on the underside of leaves. Control of a light infestation should occur in two to three weeks. On heavier infestations a second release may be required. These predatory mites will multiply nearly twice as fast as the spider mite population. They only feed on other mites, they do not feed on plants.

Parasitoids use another method to kill their prey: they lay their eggs in or on other insects. When the eggs hatch, the larvae feed on the host, killing it as it matures. Both flies and wasps are parasitoids. Fly parasitoids attack many kinds of insects including termites, bees, ants, scales, slugs, snails, crickets and caterpillars. Wasp parasitoids are tiny, non-stinging wasps that attack beetles, leafhoppers, caterpillars, aphids, whiteflies and true bugs. Most are very specific about which insect they attack.

Pathogens include bacteria, viruses, fungi, protozoa and nematodes. Insects and mites, like plants, humans, and other animals, can be infected by disease-causing organisms such as bacteria, viruses, and fungi. Diseases can be important natural controls of some insect pests.

Some pathogens, such as the bacterium, Bacillus thuringiensis or BT, are mass produced and used by gardeners to control leaf-eating caterpillars. In particular, the cabbage worm is controlled by BT. They devour broccoli and cabbage leaves when the white cabbage butterfly lays its eggs on the leaves of all members of the cabbage family. Spray weekly to control.

So be careful about killing every bug you see in your garden. A lot of them may be there helping you keep your plants healthy.