Identification Features and Control Methods of the Citrus Longhorned Beetle

The citrus longhorned beetle is an insect of the order Coleoptera, family Cerambycidae. It gets its name because its elytra are glossy black and covered with white spots, as if dotted with starlight. Its antennae are slender, the adult is medium-sized, and it is quite active. It is widely distributed in China and is a common trunk-boring pest on fruit trees and forest trees.

The citrus longhorned beetle has a fairly varied diet and many host species. A wide range of fruit trees and forest trees, including citrus, apple, pear, mulberry, fig, as well as willow and poplar, may be affected. Adults often feed on the cortex of young twigs and on leaves to supplement their nutrition, while the larvae bore into the trunk and main roots, first feeding beneath the cortex and then penetrating deeper into the xylem, expelling frass that resembles wood shavings. Affected trees may at best decline in vigor with yellowing branches and leaves, and at worst die completely.

For controlling the citrus longhorned beetle, manual measures should be combined with chemical treatment. During the adult emergence period, manual capture can be organized, and the base of the trunk should be inspected so that eggs and newly hatched larvae can be scraped off in time. When frass holes are found, the larvae inside can be hooked out with a wire, or an insecticide can be injected into the hole and the opening sealed with wet mud. Whitewashing the trunk in winter and spring can also reduce egg laying by adults.

In routine management, keeping trees vigorous and promptly pruning and removing severely affected branches and dead plants helps reduce the pest population. The control approach for other longhorned beetle pests such as the mulberry longhorned beetle is similar to that for the citrus longhorned beetle. Growers cultivating fig, mulberry, and other fruit trees can refer to similar methods for integrated control, so as to achieve early detection and early treatment.