Question: We simply can’t believe the number of aphids we have on some of our garden plants. What’s the best way to get rid of them? We have them on everything from zucchinis to plum trees.

Answer: You are not alone – there are almost as many kinds of aphids as there are plants they feed on. They come in all colors, some have wings, some are woolly, most have soft bodies. Aphids have mouth parts shaped like a hypodermic needle, which they use to pierce tender plants and suck out the juices.

Plants respond differently to aphid attacks. Some plants produce twisted or swollen leaves and stems, while others show no response at all. Aphids are notorious in commercial agriculture for transmitting plant diseases.

The most obvious sign of aphid activity is the production of honeydew, a sugary liquid excreted by the aphids themselves. Ants are often found “tending” aphids for the chance to harvest this sweet sticky liquid. Honey dew drips onto plant foliage and stems, creating a perfect medium for black sooty mold to grow. Although unsightly, the molds are superficial and harmless to plant tissues.

Aphids are masters of reproduction and adaptability. Some bear live young that begin sucking sap immediately. New females mature to produce their own offspring in less than two weeks, until the colony grows so large that they begin to produce winged forms to seek out new areas to colonize. Late in the season, they may lay eggs for overwintering.

There are several options for aphid management. The first option for aphid management is tolerance, since aphid populations are naturally regulated in many ways.

There are a number of natural controls that effectively reduce aphid populations. Ladybird beetles, green lacewings, damsel bugs, syrphid flies, parasitic wasps, and certain fungi can all lower aphid populations. High pressure water spray from a garden hose is also a good option for aphid management on smaller plants. The water spray acts much like a heavy rain knocking the aphids off the plant. Insecticides are effective in reducing aphid numbers. It is best to use the least toxic products first. A least toxic product like Safer’s Soap is an excellent choice for home gardeners since it can be used on edible food crops. Other insecticides registered for use on aphids include Orthene and Malathion. Keep in mind that these insecticides kill the natural enemies as well as aphids, and can make aphid problems worse.

Question: We sprayed an insecticidal soap on some of our plants to control the aphids. Four days later, the plants were totally infested with aphids again. Why did this happen?

Answer: Insecticidal soap must contact pests directly to kill them. It is effective only while still wet; there is no residual activity after it dries. It usually does not kill insect eggs, so repeat sprays often are necessary to control newly hatched pests.

Soap can damage certain plants. Use it according to label directions and do not use it on water-stressed plants or if the weather is very hot. Another way to avoid damage is to spray plants, let the soap dry, and then rinse it off with a spray of water.

There are many homemade recipes for insecticidal soap made from liquid dish washing detergent. These sprays are risky to use because different detergents have different concentrations of active ingredients. If a spray is too concentrated, it may harm plants. It is best to use a commercial product that has been tested on a variety of plants.

Question: Now that our strawberries have finished fruiting, is there anything we should do now to ensure a good crop next year?

Answer: You can maintain a strawberry planting for several fruiting seasons if you properly manage and renovate it after harvest. If plants are vigorous and relatively free from weeds, insects and diseases, you may renovate a matted row of June-bearers to prepare it for the next season. Renovation improves the next season’s yield and may decrease fruit rot significantly, especially if leaves are removed. Renovation is not recommended for day-neutrals or everbearers.

After the crop has been harvested, mow the foliage to about two inches above the top of the crowns. You can use hedge clippers or a rotary mower with the blade raised high. Be careful not to damage crowns. Remove all plant debris and bury it.

Narrow the rows to a strip 8 to 10 inches wide using a rototiller, shovel, or hoe (go no deeper than 1 to 2 inches).

Thin out old and weak plants leaving one year-old vigorous plants. The best plant density is about five to six plants per square foot of row.

Keep the planting weed free by cultivating. Loose soil also promotes rooting of runners. If you narrowed the row below the width desired, allow the runners to fill the desired row width. Remove all excess runners as they form. Remove all runners that form after September 1 since they won’t have time to root and form flower buds for next season’s crop.

EDITOR’S NOTE: For answers to local gardening questions, contact Master Gardener Rachel Gana at 642-8723 or e-mail her at: baiter1@pacifier.com.