Description
Root weevils are serious pests of berries, ornamentals, and grasses. Both adults and larvae cause damage. The adults are snout beetles, with chewing mouthparts at the end of their long snouts. They have light brown to black hard-shelled bodies, with rows of tiny round depressions on their backs. In most species the adults cannot fly because their elytra (wing covers) are fused down the middle of the back. The adult weevils feed at night, notching the edges of leaves. In the summer, each female lays hundreds of eggs on the soil at the base of plants. The emerging larvae are white, C-shaped, legless grubs with brown heads. The grubs sometimes feed on the base of plant stems before burrowing down into the soil to feed on roots. They spend the winter in the soil and resume feeding in the spring. Larval feeding is most severe in spring and often results in severe weakening or death of the plant.
Control
Since the grubs are protected by soil, there is no effective control for them. Control of root weevils must be aimed at the adults. The best time to spray is when the adults emerge from the soil. Check your plants periodically for notched leaves (make sure the damage is not confused with that caused by cutter bees); or contact your local County Extension Agent (see County Extension Agents) for the time of weevil emergence. On ornamentals spray the foliage and the ground under the plant thoroughly with an insecticide containing acephate. Make sure your plant is listed on the product label. Repeat the spray 2 more times at intervals of 3 weeks.
