Insecticides for Oak Trees

Oak trees (Quercus spp.) are some of the most valuable hardwood and landscape trees in the United States. Their wood is used for flooring and furniture, they provide welcome shade in the summer and they provide wildlife with food and shelter. But insect pests can threaten the vitality and even the future of an oak tree. Using proper cultural practices and insecticides will give your oak a long life.

Permethrin

Use permethrin on oak trees to control the ambrosia beetle, aphids, bagworms and other pests. It attacks the insects' nervous systems, disrupting neuron functions, causing paralysis and death, according to the National Pesticide Information Center. If you use an insecticide containing permethrin to control these pests, check weekly until all symptoms are gone. The pesticide is highly toxic to honeybees, cats, dogs, cattle, fish and aquatic invertebrates.

Imidacloprid

Use imidacloprid on oaks to control the flat-headed apple tree borer and other sucking insects. This insecticide affects the insects' nervous systems, which leads to paralysis and death. The insecticide, which is derived from nicotine, is highly toxic to aquatic invertebrates and bees. Apply it before the first egg hatch, which usually occurs in June.

Lambda-cyhalothrin

Lambda-cyhalothrin kills caterpillars such as the fall webworm, forest tent caterpillar and gypsy moth yellow-necked caterpillar. It also controls lace bugs and sawflies. The insecticide disrupts the insect's nervous system, which leads to paralysis and death. Spray the trees' leaves before the leaf damage is extensive and while the caterpillars are still small, according to SickPlant.com