Insects: It's Not All Bad News

By Sean Stowell, LCN

While there are insects that can do definite harm to trees there are also insects that are beneficial. The destructive critters interfere with sap flow and retard plant growth, but the beneficial insects can help with pollination and kill species harmful to trees.

It may be tempting to kill every bug you see, but you might be taking away nature?EUR??,,????'???s benefit to the tree. It?EUR??,,????'???s important to identify the good, the bad, and even the ugly insects when it comes to proper tree care.

?EUR??,,????'??The first thing to look for is the type of damage, and then look for the mouth parts of the bug,?EUR??,,????'?? Susan Sims of Sims Tree Health Specialists in Pedley, Calif., told LCN. ?EUR??,,????'??Also look for quantity as pests are usually in large quantities and predators are loners or in small quantities.?EUR??,,????'??

The Big Three

Basically, insects can be divided into three categories according to how they feed: chewing, sucking, and boring. According to the International Society of Arboriculture, insects from each group have characteristic patterns of damage that will help you determine the culprit and the proper treatment. If there are any questions, always consult a tree care expert.

	Chewing Insects: These bugs eat plant tissue such as leaves, flowers, buds and twigs. Indications of damage by these insects is often seen by uneven or broken margins on the leaves, skeletonization of the leaves, and leaf mining. Chewing insects can be beetle adults or larvae, moth larvae (caterpillars), and many other groups of insects. The damage they cause will help in identifying the pest.
	Sucking Insects: Suckers insert their beak, or their proboscis, into the tissues of leaves, twigs, branches, flowers, or fruit and then feed on the plant?EUR??,,????'???s juices. Some examples of sucking insects are aphids, mealy bugs, thrips, and leafhoppers. Damage caused by these pests is often indicated by discoloration, drooping, wilting, leaf spots (stippling), honeydew, or general lack of vigor in the affected plant.
	Boring Insect: All pests in this category spend time feeding somewhere beneath the bark of a tree as larvae. Some borers kill twigs and leaders when adults feed or when eggs hatch into larvae that bore into the stem and develop into adults. Other borers, such as bark beetles, mate at or near the bark surface, and adults lay eggs in tunnels beneath the bark.

The Good Guys

You?EUR??,,????'???ve learned a little bit about the harmful insects, now let?EUR??,,????'???s take a look at some that may seem harmful, but in reality can help you and your trees. ?EUR??,,????'??These bugs are faster and designed with predation in mind,?EUR??,,????'?? Sims said. ?EUR??,,????'??They often have big eyes and are built for camouflage or stealth.?EUR??,,????'??

	Damsel Bugs: Damsel bugs feed on aphids, leafhoppers, plant bugs, thrips and small larvae. They are small and elongated, with gray, brown or black bodies. Young nymphs begin feeding immediately, often on insects larger than themselves.
	Lady Bug: Also known as the ?EUR??,,????'??mealy bug destroyer,?EUR??,,????'?? the adult is oval with black wing covers while the head and tip of the abdomen are coral colored. The females lay oval, yellow eggs among the eggs of mealy bugs. The newly hatched larvae feed on the eggs of the mealy bugs for approximately three weeks.
	Lace Wing: This predator is green or brown and is very delicate looking with its wings held tent-like on its back. It is predatory in its larvae stage and is sometimes known as an aphid lion. Aphid Midge: The aphid midge can control more than 60 species of aphids. Adults are long-legged with prominent antennae and are active at night. Both the larvae and the eggs are orange.

These are just some of the more common insects you?EUR??,,????'???ll run into out in the landscape. If you have questions about insects you come across, be sure to check with a certified arborist to make sure there is a balance between the good and the bad.

?EUR??,,????'??Basically, it?EUR??,,????'???s a whole educational thing to learn about insects,?EUR??,,????'?? Sims said. ?EUR??,,????'??Instead of spraying and killing everything, it is important to treat on an as-needed basis.