It’s a Bug-Eat-Bug World
- • 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 â…›” 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.
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