What to Do About Slug Moth Caterpillars Harming Cherry Blossoms? A Detailed Guide to Prevention and Control Methods

What harm do slug moth caterpillars do to cherry blossoms? How can they be controlled?

Slug moth caterpillars mainly cause damage by their larvae chewing on cherry blossom leaves. Newly hatched larvae gather in groups to gnaw the leaf flesh, leaving the epidermis behind; after growing larger they disperse and cause damage, and in severe cases they can eat all the leaves on an entire branch.

There are many species of slug moths that harm cherry blossoms, including the brown-edged green slug moth, the Chinese green slug moth, the camphor slug moth, and the small black slug moth. Adult slug moths are mostly densely covered with scales and hairs, generally yellow-brown to green, with simple red or brown markings. Their larvae are commonly known as stinging caterpillars, with branched spines and venomous hairs on their bodies that can irritate human skin. The larvae are short and plump, oval-shaped, generally rather brightly colored, with a small head that can be retracted into the prothorax.

In North China, slug moths generally have 1 generation per year, overwintering as mature larvae in cocoons spun in soil crevices. They pupate in May of the following year, and adults emerge in June and lay eggs on the underside of leaves near the main vein. The egg masses are patch-shaped. The larval damage period is from July to August. The adults hide during the day, are active at night, and are phototactic.

Measures for controlling slug moths: First, in winter or early spring, eliminate the cocoons on branches and bark or in the soil. Second, during the damage period, promptly remove egg masses and infested leaves, crush the eggs and larvae, and avoid touching them with the skin. Third, chemical control: spray 50% fenitrothion emulsifiable concentrate at 1000 times dilution or 90% trichlorfon crystal at 1000-2000 times dilution, etc.