1. Harmful symptoms
The larvae are damaged at the root neck at the base of the trunk, and the xylem is mothed by many insect channels, and piles of wood chips and feces are discharged from the damaged area. Destroy the nutrient and water delivery of the tree, and in severe cases, lead to the death of the tree.
Prevention and control programmes
(1) Agricultural control: orchards are combined with pruning to remove diseased and insect branches, and centralized treatment. Adults are killed in time during the onset of adults and destroyed before spawning.
(2) Chemical control: during the occurrence of adult insects combined with other pests for control, the wood chips in the worm hole are eliminated, the cotton is dipped in 48% chlorpyrifos emulsion 5 to 10 times liquid into the worm hole, and then the orifice is sealed with mud, which can kill the larvae; the trunk and tree neck can also be sprayed with 48% chlorpyrifos 50 to 60 times during the peak of spawning.
3. Morphological characteristics
Adult: 19-39 mm in length, pitch black and shiny. The antennae are filamentous in 11 segments, and the base half of each section 3-11 has a pale blue hair ring. There are 3 tumors in the center of the dorsal plate of the anterior chest, and the lateral spines are thick. The base of the elytra is densely grained, and there are more than 20 irregularly arranged white hair spots on the surface of the wings. Small shields and tarsal segments are pale cyan. The eggs are oblong, 5-6 mm long, and yellowish brown after colostrum white. Larvae: 45-67 mm in length, pale yellowish-white. The head is yellowish brown with a black upper jaw; the front and left sides of the dorsal plate of the anterior thorax have yellow-brown bird-shaped markings, and there are 1 yellow-brown "convex" glyph-shaped large spots slightly raised in the rear; the thorax and foot are degenerated; the ventral surface of the middle thorax, the posterior chest, and the dorsal and ventral surfaces of 1-7 abdominal segments have oblong step bubbles. Pupae: 30 mm long, colostrum white after black brown.
Fourth, life habits
The second anniversary of the Tianniu occurs in one generation, overwintering as larvae or adults. Most adult worms emerge from May to July, and adults lurk in the cave during the day and out of the cave at night, especially at 8 to 9 o'clock in the sweltering night before the rain. Adults lay eggs in the bark crevices of trunks and large branches above 0.5 m above the ground, and mostly inhabit the branches on rainy days; eggs are mostly born at noon on sunny days, at the forks of tender green twigs or at the intersection of petioles and twigs. Eggs hatch from mid-June to early July. The larvae first feed upwards, and then moth downwards when the twigs are difficult to accommodate the insect body, causing the twigs to die.
5. Hazards
Causes wounds, affects the water conduction of the tree, and the tree dies.