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

What are systemic insecticides?

A systemic insecticide is a granular or liquid pesticide which travels through the plant's vascular system, and is absorbed into the tissues of the plant. There it repels or kills most of the kinds of insects which feed upon the plant. Systemic insecticides are most commonly applied at the base of the plant, or as a soil drench. The insecticide is absorbed by the roots of the plant, and then moves to the above-ground parts (leaves, twigs and branches), where it is toxic to sucking or chewing insects. Systemics may remain toxic in the plant for several weeks.

Systemic insecticides are especially effective against insects such as scale, which feed on plant sap but are protected by an impermeable body covering. They are also effective against mining and tunneling insects which invade inside the plant. They are useful in treating some ornamental crops, but can result in potentially dangerous levels of toxicity to humans and animals when used on or near edible crops.

Systemic insecticides must always be used with care. Read and follow the label directions carefully to ensure that both the plant and pest are listed for product use. To reduce the potential for water run-off contamination, never exceed application rates when applying systemics to the soil.