The Secret Life of Ladybugs

Friday, May 25th, 2012 by Jenny Watts
    • Plant the vegetable garden this month, but remember that late frosts can still nip tender young plants.
    • Beautiful African Violets will decorate your indoor spaces with their masses of flowers in all shades of purple, blue and pink.
    • Feed roses to encourage a beautiful display of color later this month. Treat plants to prevent insect and disease problems.
    • Azaleas, camellias and rhododendrons provide lots of beautiful flowers for the shady spring garden. Choose now.
    • Petunias can be planted now. Their bright flowers will bloom all summer in hot, sunny locations and they will take a light frost.

The Secret Life of Ladybugs

Ladybugs, also called lady beetles or ladybird beetles, are magnificent creatures. They are predators and are natural enemies of many insects, especially aphids and other sap feeders. A single lady beetle may eat as many as 5,000 aphids in its lifetime. In addition to aphids, ladybugs eat a variety of other insects and larvae including white flies, mealy bugs, spider mites, and other types of soft-bodied insects.

In California we are familiar with Convergent Lady Beetles. They are dome-shaped and have red wings with the usual 13 spots, or sometimes none. One or two generations occur each year before the adults go into hibernation, usually in mountain valleys far from food sources.

Adult females usually lay clusters of eggs on plants in the vicinity of aphid, scale, or mealybug colonies. Females may lay from 200 to more than 1,000 eggs over the summer. In two to five days, the eggs hatch and alligator-like larvae appear. They are spiny and black with bright orange spots on their backs and, although they look dangerous, they are quite harmless to humans. They are excellent predators and, while adult ladybugs tend to move on once pests get scarce, the larvae remain and search for more prey. They have a voracious appetite for aphids and feed for 3 to 4 weeks before they pupate and turn into young adult ladybugs.

You can purchase ladybugs from most nurseries in the spring and early summer. Before releasing them into your garden, here are a few tips to help ensure that the ladybugs stay where you want them:

1. Release ladybugs near infested plants after sun down or before sun up. They navigate by the sun and are most likely to stay put in the evenings and early mornings.

2. Water the area where you are going to release the ladybugs. They will appreciate the drink and the moisture on the leaves will help the ladybugs to “stick” on the plants. If released in a dry garden, the ladybugs will most likely fly off in search of a drink instead of sticking around to eat.

3. In warm weather, chill the ladybugs in the refrigerator before releasing them. This will not harm the ladybugs and they tend to crawl more in colder temperatures rather than fly away.

Do not release too many Ladybugs at one time. Try to keep a balance of pests and Ladybugs so that they have something to eat. Release a few at a time each night when leaves are young, tender and attractive to aphids.

Greenhouses often attract aphids and other pests due to warm humid conditions and abundant food. Releasing ladybugs into a greenhouse with screened doors and openings will keep them inside where you need them.

As winter approaches, lady beetles migrate to the Sierra Nevada Mountains where they congregate in large numbers before moving off to hibernate under nearby pine needles and leaf litter.

Throughout the world ladybugs are a symbol of good luck. And they will bring “good luck” to your garden by keeping it clean of undesirable pests.

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.