Japanese beetle
Metallic green and copper beetles that skeletonise leaves and devour flowers in summer, while their grubs feed on lawn roots.
Also known as: Popillia japonica
Symptoms and identification
Leaves are eaten between the veins, leaving a lace-like skeleton. Roses and other flowers are chewed, often by groups of beetles. Brown patches appear in lawns where white C-shaped grubs eat the roots.
Causes
Adults emerge in early summer and are attracted to damaged plants and other beetles. Native to Japan, they are a major pest in North America and parts of Europe.
Organic treatment
Knock beetles into a bucket of soapy water in the early morning. Cover small plants with insect netting during peak season. Neem oil deters feeding on lightly affected plants.
Prevention
Check plants daily in early summer. Avoid traps in the garden, which can draw in more beetles. Treat lawns for grubs with beneficial nematodes or milky spore in late summer.
Chemical treatment (use with care)
Use an insecticide labelled for Japanese beetles on that plant, avoiding open flowers visited by bees.