Arrow-right Camera
The Spokesman-Review Newspaper

The Spokesman-Review Newspaper The Spokesman-Review

Spokane, Washington  Est. May 19, 1883
News >  Spokane

Gardening: Defending against aphid invasion

Aphids cause distortion of the leaves on this currant. A predatory lady beetle will soon lay her eggs, and the larvae will eat the aphids. (Pat Munts / The Spokesman-Review)
Aphids cause distortion of the leaves on this currant. A predatory lady beetle will soon lay her eggs, and the larvae will eat the aphids. (Pat Munts / The Spokesman-Review) Buy this photo

If we can get just a few more days of warm weather, the roses will begin coming into bloom. And with them will come a bevy of insects to steal away their beauty.

Rose breeders have done wonders in the past few decades to breed roses that are hardier and less prone to disease and bug issues, but they haven’t completely eliminated the potential of roses being attacked by aphids.

Aphids are green or pinkish, pear-shaped, soft-bodied insects that cluster around the flower buds. They are generally less than a quarter of an inch long. Some of the first signs of aphid damage will appear as wrinkling on the buds and puckered and curling new leaves. The insects are there to suck plant juice out of the tender new growth.

Unfortunately for gardeners, aphids reproduce quickly and without mating. The females give birth to live young that can mature in a week and continue the breeding process until it gets cold in the fall. Over time, the sticky sweet sap created by the feeding aphids attracts ants that in turn tend to encourage them to produce more honeydew. Over time, black sooty mold grows in the sap, making the plants even less appealing.

Controlling aphids effectively doesn’t mean reaching for the can of bug spray as soon as you see an aphid. That can actually create more of a problem because the kills-all spray also does away with the predator insects that may be snacking on the aphids. Without this cadre of often invisible destroyers, the aphid population can explode again after the chemical washes off the leaves or loses its effectiveness. A few aphids are a good thing because they draw in the predators, whose numbers increase so they are ready to go as the aphid population expands.

With a little tolerance and patience, nature just might take care of your aphid problem without you raising a finger.

The next line of defense is to use a strong jet of water to blast the aphids off your plants. This will knock them to the ground and disrupt breeding enough to slow the infestation down. Done once a week when the flower buds are just forming, you can probably avoid problems at the height of the bloom period.

If you have to use a chemical, use insecticidal soaps, such as Safer Insecticidal Soap, to do the job. These soaps dehydrate the aphid bodies or suffocate the insects. The spray has a fixative in it to hold it to the leaf for a while or during rain or irrigation. These soaps are also effective on mealy bugs, scale and many other insects. Read the label for a complete list and follow the directions.

While it is better to use commercial insecticidal soaps, you can make your own. Simply mix five tablespoons of pure castile soap in a gallon of water. Add two tablespoons of cooking oil per gallon of water to act as a sticking agent. Reapply every couple of weeks.

Pat Munts is co-author of “Northwest Gardener’s Handbook” with Susan Mulvihill. She can be reached at

The Spokesman-Review Newspaper

Local journalism is essential.

Give directly to The Spokesman-Review's Northwest Passages community forums series -- which helps to offset the costs of several reporter and editor positions at the newspaper -- by using the easy options below. Gifts processed in this system are not tax deductible, but are predominately used to help meet the local financial requirements needed to receive national matching-grant funds.

Active Person

Subscribe now to get breaking news alerts in your email inbox

Get breaking news delivered to your inbox as it happens.