Leaf-eating beetles are a natural part of the environment and, often, their damage is minimal and of little concern. However, if your garden is infested with beetles and they are feeding in masses on your ornamental plants or crops, action is necessary. Beetles can potentially kill plants, turn leaves into unsightly skeletons and reduce crop yields. Don't fret, though, for there is an easy way to kill beetles, and with a bit of persistence, you can keep their population under control so they do little, if any noticeable damage.
Wait and watch for the leaf-eating beetles to emerge from the ground. This may happen in the spring, summer or fall, depending on the type of beetle and climate in which you live.
Fill a pail with soapy water and examine the plants in your garden in the early morning or late evening when beetles tend to be more sluggish. Look on the underside of the leaves where many beetles are located.
Pick off the beetles and throw them into the soapy water, which kills them. Or, place the pail under the plant and knock them in. You can also try shaking the plants so they drop into the pail. Manually remove the beetles every day as necessary to help control the leaf-eating beetle population in your garden.
Spray plants with an insecticide, such as carbaryl, permethrin or bifenthrin, labelled to kill the kind of leaf-eating beetles in your landscape. Use insecticides per label instructions and verify that it is safe for the plants on which you plan to use it.
Beetle traps often attract more beetles to your landscape than they kill. Trapping can work, though, if all your neighbours set up traps also.