How to Kill Boxwood Beetles

Spray the ground around your boxwood with an insecticide containing imidacloprid. Wear gloves and protective eyewear when spraying. Apply the chemical between February and early April to kill boxwood leafminer larvae in the soil. The pesticide is available under different brand names. Read the manufacturer’s label on the product you select and use the spray accordingly.

Examine the underside of the boxwood leaves for pupae and adult leafminers. Pupae look like very small cocoons and the insects, like mosquitoes that range from yellow to red. If either form of the pest is present on the foliage, spray it with dimethoate, carbaryl or malathion in April. Use the product according to the brand’s instructions. The University of Tennessee website recommends retreating the leaves in mid-May with a combination of dimethoate, cyfluthrin and imidacloprid.

Treat heavy infestations of boxwood psyllids with a pesticide that contains acephate or carbaryl for spraying the foliage and dinotefuran or imidacloprid for soil application. Choose a brand and use the product according to the label instructions. Boxwood psyllids are green, have see-through wings and are 1/8 inch long. The insects move by flying or jumping.