Morphological Characteristics and Damage of the Jujube Carpenter Moth

The jujube leopard carpenter moth belongs to the order Lepidoptera, family Zeuzeridae. It is also called the trunk-cutting worm. The adult has a body length of 18-22 mm, a white head, a grayish-white thorax and abdomen, filiform antennae, and 6 blue spots on the back of the thorax arranged in 2 longitudinal rows. The forewings are scattered with irregular blue spots of varying sizes, while the area before the submedian fold of the hindwings is covered with narrow blackish-blue transverse bands, and the marginal spots of the wings are darker in color.

The eggs are spherical, pale yellow when newly laid, and densely covered with reticulate sculpturing.

The larva has a body length of 30-40 mm, a yellowish-brown head, a purplish-red trunk, and a black pronotum with 2 black spots and 4 rows of black spines along the posterior margin. The anal plate is black and glossy.

The pupa is obtect, curved spindle-shaped, and faded in color.

This insect is mainly distributed in South China and North China. In addition to damaging jujube, it also damages apricot, pear, walnut, black locust, and others. The larvae bore into the phloem of jujube fruiting shoots and tunnel within the xylem, causing the fruiting shoots to wither. Especially after damaging young trees, it forms stunted trees that cannot bear fruit, greatly affecting jujube yield.

Life Habits and Control Methods of the Jujube Leopard Carpenter Moth

This insect has one generation per year, overwintering as larvae in the tunnels of damaged branches. After sap flow begins the following year, the larvae start feeding on the xylem within the pith tunnel, and at regular intervals chew openings to the outside to vent air and expel frass. Mature larvae enter the peak pupation period in early July. Before pupation, they plug both ends of the tunnel with frass and bind it with silk, pupating inside. Adults are phototactic, resting during the day and flying at night to mate, laying eggs on young trees and new jujube shoot branches.

After hatching, the larvae begin boring in from the base of the leaf stalk and feed on the xylem of the fruiting shoot. As the larval instar and body size increase, they begin to move to secondary branches, primary branches, or the trunk of young trees. They first gnaw the cortex, feed on the xylem, and reach the pith, feeding from bottom to top. Before overwintering, they mostly turn back and bore downward, and block the tunnel opening within thicker branches to overwinter.

Control methods:

(1) Conduct a general survey of dead branches in early May. If dead branches are found, or if jujube shoots have sprouted, prune the branches 20-30 cm below the dead branch. After finding insect holes, split them open and kill the larvae.

(2) During the peak emergence period of adults, use light traps or bonfires to kill the insects based on their phototaxis.

(3) Locate the boring holes and inject a 100-fold dilution of 50% methyl parathion into the holes along the tunnels to kill the larvae in the branches and trunk.