How to Kill Vine Weevils

Vine weevils are common garden pests that often attack azaleas and rhododendrons. Weevils lay larvae that burrow into the soil around the plants and feed on the roots. When the weevils hatch, the adults migrate to the foliage of the plants and chew notch-shaped holes into the leaves. This leads to the plant's death if the weevils are not controlled. Killing vine weevils involves breaking the reproduction cycle by eliminating the adults first.

Things You'll Need

• Bucket
• Soapy water
• Light-colored cloth
• Flashlight
• Nematodes
• Sackcloth
• Foliar insecticide
• Thiacloprid insecticide

Instructions

1. Fill a bucket with soapy water. Take the bucket and a flashlight outside to your garden at night. Vine weevils are most active at night. Lay light-colored cloth under each plant. Inspect each plant for adult weevils. Pull them off the plant, and dunk them in the soapy water to drown them. Any weevils you drop you should be able to spot on the light cloth.

2. Purchase beneficial nematodes, which will kill vine weevils in the soil around your plants. The species Steinernema kraussei and Heterorhabditis megidis are effective and available from garden centers. Mix the nematodes in water according to the package directions, and pour the water into the soil around the plants. Apply them between March and May or between August and November.

3. Lay a moist piece of sackcloth around the base of the plants during the day. The weevils will climb into it for shelter. At the end of the day, dunk the sackcloth into a bucket of soapy water.

4. Apply a foliar insecticide once a month to the leaves of the infected plants. This will kill the adults, stopping them from laying eggs, and breaking the life cycle of the population. Reapply the insecticide once a month to kill any larvae that hatch.

5. Apply an insecticide containing the chemical thiacloprid as a soil drench surrounding the infested plants. Follow application instructions on the package.

References

• BBC: Black vine weevil
• Down Garden Services: Vine Weevil
• American Rhododendron Society; Practical Black Vine Weevil Management; Richard S. Cowles