Is your garden under attack? First know your enemy.

BILL AND DENISE ASK: What is damaging our young French prune tree? Most of its leaves are curled and very distorted.

We would hate to lose the tree! There are several of these beetle-like insects crawling all over the tree. Their heads are an orange color and their elongated bodies have dark brown wings.

On closer inspection, you have a large population of leaf curl plum aphids. Also visibly apparent are very small white flecks from their shed skins. Ants are moving up the tree trunk feasting on the sticky honeydew created by the sucking aphids.

The good news is, you have a decent number of predatory insects called soldier beetles or leather-winged beetles that feed on aphids, mealy bugs and other soft-bodied insects. So, your suspected culprit is one of the good guys! You should allow the (elongated) soldier beetles to do their job eating the aphids. If you are lucky, ladybugs (lady beetles) will appear and they too will feast on the aphids.

Early in the day you can use a forceful spray of water on the tree and that should knock down the aphids. Once the aphids are knocked to the ground they won’t come back on the tree. Natural enemies will take care of the rest. The forceful spray of water will also wash off any honeydew that has formed.

If you no longer see any natural enemies, try using a solution of 2 to 3 tablespoons of a mild liquid dishwashing soap to 1 gallon of water for aphid control. Or you can purchase a commercial product from the Safer line that targets aphids. A word of warning: do not use any soap sprays on plants during hot and humid days or when the plant is water stressed. Spraying early in the morning or late evening is best.

If the tips of the prune branches are looking black, cut those areas back to a healthy and newly forming side bud. Spray your shears with Lysol after cutting to avoid transferring any other disease that may be present.

Plan ahead for next year (late winter) by spraying your French prune with a dormant oil to prevent another outbreak of leaf curl plum aphids. There is no need to spray all surrounding vegetation because many aphids are host specific, meaning they will only feed on a specific tree or plant.

WHAT ARE SUCKING INSECTS? Sucking insects have sucking mouthparts that feed by sucking sap from the plants. In extreme numbers there can be a decline in plant vigor.

They will excrete large amounts of sugary honeydew and that in turn allows growth for an unsightly blackish sooty mold on leaves. Aphids have sucking mouthparts and can cause leaf curling and discoloration and transmit viruses.

Then there are the insects who chew. They chew holes in leaves, in fruit, along leaf edges and even inside leaves (leaf miners).

The name refers to the damage they are capable of doing. An example would be the spotted cucumber beetle that may be found on squash and melon blossoms and yellow ornamental flowers.

Damage by cucumber beetle larvae is evident by retarded plant growth on young plants. Adult beetles can transmit a bacterium from plant to plant that produces a wilt in curcubits (squash, pumpkins, melons, gourds) and a cucumber mosaic virus.

Snails, slugs and caterpillars can decimate new seedlings and cause leave ugly holes in leafy vegetables such as chard and tomato fruit, to name a few.

Spraying toxic chemicals without proper identification of a suspected insect is not recommended. Knowing their specific mouthparts that do the subsequent damage, is helpful in identifying the insect.

Knowing and understanding the large array of natural enemies is even more helpful when identifying the “good guys” versus the “bad guys,” thus eliminating any confusion when addressing insect problems.

Lady beetles feed on pest mites, aphids, scales, whiteflies, psyllids and scales. Soldier beetles eat aphids and the eggs and larvae of beetles and moths.

EDNA WRITES: What causes the red discoloration on heavenly bamboo? I thought it was the cold weather but the leaves remain colorful during all the seasons. I do enjoy the colorful foliage and the plants always appear healthy.

The discoloration on your heavenly bamboo, also known botanically as Nandina, is a virus infection that is spread by aphids (sucking insects).

As they feed on infected plants they transmit the virus as they move to and feed on others nearby plants. There is no cure, so enjoy the colorful leaves but continue to keep your Nandina healthy.

Dana Lozano and Gwen Kilchherr are garden consultants. Send your gardening questions to The Garden Doctors, at pdgardendoctor@gmail.com. The Garden Doctors can answer questions only through their column, which appears twice a month in the newspaper and online at pressdemocrat.com.