Identification and Control Methods for the Great Spruce Bark Beetle

The great spruce bark beetle [Dendroctonus micans (Kugelann)] belongs to the order Coleoptera, family Scolytidae. It is mainly distributed in Austria, Belgium, Czech Republic, Slovakia, Denmark, Finland, France and other countries. In China, it has been found in the Makehe forest area of Qinghai Province. It mainly damages some species of Picea (spruce), and occasionally some species of Pinus (pine) and Abies (fir), as well as European larch and Douglas fir.

Damage characteristics: adults and larvae attack weakened trees and dead standing trees; during outbreaks, they can attack healthy trees, severely disrupting the trees' transport function, leading to weakened tree vigor and even death.

Morphological characteristics unknown

Occurrence pattern: it is a boring, secondary pest. In the Makehe forest area of Qinghai Province, it has 1 generation per year, overwintering as adults or larvae under the bark of infested trees. Late April to mid-May is the beginning of the damage period (adult emergence and flight period), June to July is the peak damage period, and mid-August is the end of the damage period. Under normal circumstances, it damages weakened trees and dead standing trees; during outbreaks, it can attack healthy trees.

Control methods

(1) Strengthen quarantine to prevent spread through seedlings, timber and other means.

(2) Strengthen forest management.

① Create mixed forests, strengthen tending, enhance tree vigor, and reduce damage;

② Pay attention to forest hygiene, cut down infested trees and wind-broken trees, promptly peel the stumps, and burn them in time.

③ From April to early and mid-May, before adult emergence and flight, taking advantage of the pest's habit of preferring to lay eggs and reproduce on newly felled logs, use the treetops of already felled weakened and dying trees, as well as branches reserved from tending and pruning, to make trap logs on site for control. Trap logs are 1.5-2 m long, placed in groups of 3-5, supported on wooden blocks, with 2-4 groups placed per mu, set in forest clearings to attract adults to come and lay eggs. Before the pests on the trap logs emerge, peel the trap logs. Carry out the first peeling around June 10, remove the peeled bark from the forest in a centralized manner and handle it promptly, and replace with new trap logs; the second peeling treatment should be completed before mid-August.

(3) Protect and utilize natural enemies such as woodpeckers.

(4) Chemical control.

① Trunk pest-hole injection. Use 40% omethoate emulsifiable concentrate at 100 times dilution or 25% beta-cypermethrin at 50 times dilution, and inject into pest holes on the main trunk of lightly infested trees with a syringe, with 5 mL of pesticide injected per hole.

② Spray control. From April 20 to May 10, during the period of adult emergence and flight damage, use 40% omethoate emulsifiable concentrate at 500-1000 times dilution or 25% beta-cypermethrin at 500 times dilution to spray the tree trunks and the ground of the felling area. Each 7 days constitutes one efficacy period, and spraying is applied 3 times consecutively.

Common pesticides: omethoate, beta-cypermethrin,.