Gardening: Insects not always ‘pests’

Less than one half of one percent of all insects are considered pests on plants. Many beneficial insects feed upon harmful ones. It is important to learn to identify these beneficial insects and to recognize when they are holding pests in check.

Many insects merely rest on the plant and are neither pests nor beneficial. Learn to determine when a pest is present in damaging numbers and to evaluate the potential of the predator or parasite population to control these pests. This will help you to use fewer chemicals in your yard. The following are a few you might find around your yard now.

Bougainvillea caterpillar and moth

This is a very persistent and damaging pest of bougainvillea. The caterpillar is about one inch in length and is green in color. It eats the leaves and is often found in rolled up leaves.

When the bougainvillea is touched the caterpillars drop unobserved to the ground leaving most people wondering what is eating their bougainvillea plants. The moth which lays the eggs from which the caterpillars develop is about one and one fourth inches in length and is brown in color. The moth is busy laying eggs during the warmer months.

Chemical controls include thuricide, dipel, or sevin. Dipel and thuricide are a more natural control using bacillus thuringiensis which will control only caterpillars and will not harm the beneficial insects such as parasitic wasps.

Chinch bugs

Chinch bugs are very small insects. The adult chinch bug is only about one sixth of an inch long. The young chinch bugs are orange-red very small specks. The red color changes to brown, then dark brown to black with white wings.

Chinch bugs seriously damage St. Augustine grass with the injection of their salivary juices when they suck the sap from the grass. Damage will appear first as a yellowing of grass blades in a small area. The area will then turn brown and begin to spread with the edges of the area remaining yellow.

If you part the blades of grass at the edge of the damaged area you will see the chinch bugs running around in the soil area and on the base of the blades. It is sometimes necessary to check several spots before you find them. You can also cut the ends off a coffee can and stick it through the grass into the soil. Fill it with water and within a few minutes chinch bugs will float to the surface. Chinch bugs will be more active when the rains of June begin.

Chemical controls include Talstar. Beneficial insects include the black big-eyed bug which is about the same size as the chinch bug and can be confused with them. Look for the larger eyes and more robust body of the big-eyed bug. The Earwig is another good predator of the chinch bug. These are scary looking bugs with pincers on their posterior. An adult earwig has been known to eat as many as fifty adult chinch bugs in one night.

Aphids

Aphids are small, soft bodied, sucking insects about one sixth of an inch long. They have a pear like shape with fairly long antennae. They also have a pair of projections on their posterior.

Aphids cause damage to plants as they suck the sap from the leaves and stems. They only feed on young growth. The leaves curled by their feeding will never be normal again and flower buds may drop off. They produce honeydew which then grows sooty mold. They are also carriers of many virus diseases of plants.

Most aphids are wingless females which give birth to live young without mating. At times winged males and females are produced. These mate and fly off to other plants where eggs are deposited. Wingless females are produced from these eggs.

Chemical controls include horticultural soaps or oil. Beneficial insects are Ladybugs, Aphid Lions and Lacewings. Lacewing eggs are a small round egg on the end of a fine hair sticking straight up off plant leaves. Ladybug larva can be mistaken for mealybugs.

Cutworms

Cutworms are large caterpillars up to two inches long. They are greenish-gray to brown and smooth and soft. The cutworm usually feeds at night by cutting plants off at ground level. It can be found in the soil at the base of the plants. The adults are large, night flying moths. Cutworms can nip off several vegetable or annual flower stalks in a single night. It will look like someone was in your garden stepping on your plants. There are several species of cutworms in Florida and they are common throughout the year. There are also some cutworms that climb plants and eat the leaves of plants at night. These are called climbing cutworms.

Chemical controls include Dylox bait applied in late afternoon. Beneficial insects are Wheel Bugs, Caterpillar-Hunter Beetles and Paper Wasps.

Go on-line and google some of these beneficial insects to learn what they look like and if you see them in your garden protect them! As they multiply your use of chemicals will begin to dramatically drop.

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Eileen and Peter Ward have owned a landscape and lawn maintenance company for 35 years. Eileen can be reached at Gswdmarco@comcast.net or 239-394-1413.