Gardening Help FAQs

Here are answers to some of the most common questions we receive about garden plants. You will find concise information on general gardening techniques as well as plant selection and care. For detailed information on specific plant pests and problems refer to our Common Garden Pests and Problems page.

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Horticulture Questions and Answers

Which insects are beneficial?

Many common insects are truly beneficial because they seek and destroy insect pests. This small, but important group of insects, includes both predators and parasites. Common predators include ladybird beetles, ground beetles and praying mantids who feed directly on pests. Parasites include several tiny wasps and some moths and butterflies. Most go unnoticed or are mistaken for harmful insects. They are one of natures ways of keeping insect pests in check but often their number may be insufficient to control a pest outbreak. Beneficial insects occur naturally but many can also be purchased locally at specialty stores or mail ordered.

Beneficial insects can and do control insects but results are often mixed. Several factors increase their effectiveness. First, there must be insects present for beneficials to eat or parasitize. If food isn't available or is eaten up, the beneficial will go elsewhere to find food. This also means that you will have to tolerate a low level of pest insects in your garden to provide food for the beneficial insects.

Ladybugs are more likely to stay close to the release site if a water source is available. This could simply be droplets of moisture from a hose sprayed on nearby plants. Ladybugs are also less likely to fly away if they are released in the evening hours and spend their first night in your garden.

When using benefical insects be very careful when using certain pesticides. Broad spectrum pesticides will kill beneficial insects as well as pests. If you do need to use pesticides spot treat only and avoid treating large areas to limit damage to beneficial insects. Insecticidal soaps and horticultural oils are good choices should a spray be necessary to reduce the damage level before beneficial insects are introduced or their population builds naturally in the garden.