The damage pattern names the culprit: ragged holes and eaten edges usually point to caterpillars, leaves chewed down to a lace of veins point to beetles such as Japanese beetles, and silk tents or hanging bags point to tent caterpillars or bagworms. Matching the control to the insect group stops the feeding, since caterpillar treatments and beetle sprays are not interchangeable.

Why does the type of chewer matter for control?

Because caterpillars and beetles respond to different treatments. Caterpillar controls such as BTK, a natural bacterium, and spinosad, made by fermenting a soil bacterium, work only after caterpillars eat treated leaves, while beetles need a spray that lists them on its label.

How can the chewing pattern be read?

By the shape of the damage and what is left nearby:

• Holes, ragged edges, or whole leaves gone, often with droppings below: caterpillars such as cankerworms or spongy moth
• Leaves skeletonized to the veins: beetles such as Japanese beetles
• Silk tents in branch forks or small hanging bags: tent caterpillars or bagworms
• Pale winding trails inside the leaf: leafminers

How are caterpillars stopped?

With a spray they eat on the foliage. Where a BTK spray stays active on tree leaves for about 7 to 10 days, Garden Insect Spray with Spinosad, sprayed onto the leaves, stays effective for about 3 to 4 weeks against caterpillars, bagworms, tent caterpillars, webworms, and leafminers.

How are leaf chewing beetles stopped?

With a spray whose label lists them. Mixed at 1 ounce per gallon of water, Bug Buster II Insect Spray is applied around trees and lists Japanese beetles among the pests it controls.

Frequently Asked Questions

What if a tree with beetles is too tall to spray?

Trunk injection is an option. Deposited into holes drilled about 1/2 inch deep at the root flare, Multi Insect Killer Tree Injection Kit gives season long control of Japanese beetles and other listed pests, with control that can start to show within two weeks.

When should a BT caterpillar spray be applied?

Late in the afternoon or on a cloudy day. BT breaks down in sunlight, and treatments are repeated every 7 to 10 days if needed.

Can a trunk band stop caterpillars?

For many kinds, yes. A barrier on the trunk interrupts caterpillars moving up and down the stem.

Can a tree recover after losing many leaves?

Usually, if it was healthy beforehand. Healthier trees are also less likely to become infested in the first place.