Beetles are fascinating insects with a wide variety of colorful families and species. Some are beneficial, feeding on other insect, while other species are just plain pests. All beetles are in the order Coleoptera. Common among all adult beetles are two pair of wings, with front wings being thickened and leathery that completely cover the membranous hind wings. Adults have large compound eyes and chewing mouth parts.
Beetles have complete metamorphosis containing four life stages; egg, larva, pupa and adult beetle. Larvae have chewing mouth parts, and simple eyes which detect light, dark and movement, but cannot see as well as adult stage with the compound eyes. Different species of beetles differ in larval form. Some are c-shaped grubs with six legs, and others are wireworms with no legs. The common grubs found in the lawns will develop into beetles.
Control of all beetles can be achieved by hand picking adults and larval stages. Grubs in turfgrass are treated when grubs are newly hatched during the end of May through July by using Imidacloprid or Chlorotraniliprole as the active ingredient. Parasitic nematodes can be applied to lawns to infect the grubs, eating their insides so they never develop into adult beetles. Milky spore is a bacterial disease that affects only Japanese beetle grubs, although it has limited efficacy here in Connecticut.
In the vegetable garden, monitor known host plants by turning over leaves to look for eggs to crush them by hand. Insecticidal soap sprayed directly on any larvae will kill them by suffocation. Spinosad is an organic insecticide that will kill larval stages, too. Monitor for natural predators that would keep the pest population under control. Using broad spectrum insecticides will kill the good guys as well as the pests.