Spruce root bark beetle

Spruce root bark beetle (HylastescuniculariusErichson) belongs to the family Coleoptera, which is distributed in China and Sichuan. It is mainly harmful to spruce, especially to artificial regeneration seedlings.

The damage features feed on the roots of spruce seedlings and damage the newly felled stumps of trees.

The morphological characteristics of the adult are about 4.5mm, dark brown, slightly glossy and sparse bristles. The forehead is narrow and long, covered with shallow, dense and dim sum engraving points, the lower half of the forehead is low and flat, the upper part protrudes, and the highest point is between the eyes. The length and width of the forechest dorsal plate are about equal, and the dense engraving points are often connected in strings, the interval is narrow, or the protuberances are granulated without interval, and the dim sum produces a short hair. The length of the sheath wing is 2.7 times that of the forechest dorsal plate and 1.9 times the width of the two wings; the round dots in the grooves are arranged regularly and the snacks are glabrous; the hairs in the grooves grow gradually, and the small bristles are obvious in the wing base, and become large bristles, 3-4 horizontal rows and no vertical hairs in the middle of the wings.

The occurrence pattern occurred in the first generation of the western Tianshan Mountains, and the adults overwintered in the phloem of the newly cut stump. Before mating and spawning in June, the adults fly away from the overwintering ground to feed on the roots of spruce seedlings, and then invade the new stumps for feeding, mating and spawning. Because the lateral root of the old cutting pile no longer invades after decay, the newer spruce seedlings on the new cutting site suffer heavily, while those on the old cutting site suffer little or no damage.

Prevention and cure method

(1) strictly carry out quarantine to prevent seedlings. The wood is spread.

(2) strengthen the management of forest area.

Build a mixed forest, combined with tending and cutting, strengthen the tree potential; pay attention to the hygiene of the forest area, remove pest trees and wind-broken trees; under the premise of good sanitary conditions, small diameter trees are cut in the middle of April, bait trees are set up, and then peeling treatment is carried out.

(3) protect natural enemies such as pedestrians, parasitic wasps and woodpeckers.

(4) Pesticide control.

From the end of May to the beginning of July, during the peak period of adult flight and invasion, the branches of living trees were sprayed with 2.5% dioxin ointment 200 times or 30% cypermethrin poison ointment 500 times to control adults.

Commonly used agents are dimethrin and cypermethrin.