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.
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.
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.
ABOUT THE AUTHOR: California Certified Nursery Professional Jenny Watts is Co-owner of Sanhedrin Nursery in Willits. Visit www.sanhedrinnursery.com.