Sometimes we gardeners find ourselves in a tough spot. Let's say that we have aphids feeding on the leaves of our favorite plants. The leaves are curling and the plants do not look well.

Should we spray insecticides to control pest insects that are damaging our plants? Or, should we depend on the beneficial insects in the environment to control the pest? To spray or not to spray, that is the question.

Aphids on apple leaves and other plants can be a common occurrence in the spring. The insects use a needle-like mouthpart to pierce plant cells and extract the sugary liquid inside. The aphid feeding can cause newly emerging leaves to curl and eventually die if aphid populations are not managed. The question is, should we immediately resort to insecticides or should we rely on beneficial insects to control the pest?

Beneficial insects are those arthropods that eat insects that we consider pests. These insects are predators or parasites and are in the landscape environment looking for prey or victims. As long we do not interfere in this natural process, beneficial insects can do an excellent job controlling insect pests. Learn more about beneficial insects.

The yellow eggs in the above picture are ladybug eggs. Ladybug larvae are voracious eaters of aphids. Ladybugs can control a pest insect population such as aphids.

Attract and keep beneficial insects by planting alternative food sources that provide pollen and nectar. Plants such as daisies, Queen Ann’s lace, yarrow, alyssum, golden rod, alfalfa, clovers, and vetches will attract beneficial insects.

Water sources attract beneficial insects as well. Birdbaths, temporary puddles, small dishes of water, and dripping water can be easily installed in any garden. Remember to replace your water every few days to avoid mosquitoes and to keep it attractive. Place small ‘perches’ in water sources so that insects can access the water.

The final way to encourage beneficial insects is to provide them shelter. Areas that are left undisturbed benefit insects. Allow forest edges to grow wild and do not mow open areas unnecessarily. Plant perennial flowerbeds that will flower all season by staggering different species throughout the bed. Hedgerows also provide beneficial insects with shelter.

Non-pesticidal pest control methods do exist. A water hose is one of the most effective least toxic devices you can use to get rid of pests. Aphids, lace bugs, and spider mites can be washed away with a heavy stream of water. These pests become disoriented and find it difficult to find their way back to the plants.

Try rinsing insects such as aphids off of the plant with a strong stream of water every day for three days. After this rinse plants with water each week, especially during dry weather. Tiny insects thrive during dry weather because rain would rinse many of their number off of plants. If you can reduce the adult population of the pest insect on your plant with a stream of water perhaps you could avoid spraying a pesticide.

Another effective, less toxic control option is to pick insects off by hand or prune them out. This method is effective for larger pests such as bagworms, tent caterpillars, and fall webworms. Destroy the pests or bag them and place them in the trash.

Use Biorational insecticides if you do decide that rinsing plants isn't solving your pest problem. Soaps, oils (Dormant, Summer and Superior), naturally derived botanical insecticides (ex. Neem), and insecticides derived from naturally occurring bacteria such as Bacillus thurengiensis products (Bt, Dipel) all provide good control without polluting the environment.