| 摘要 |
There are several methods of fighting against pests.Among the largest used method is chemical control which is harmful to the environment. Most bark beetles attack susceptible trees in the spring and early summer.Killing these beetles in late summer and early fall is better ,even few killing tactics are available. Burning is hazardous and the commercial value in the trees is destroyed.Debarking is prohibitively expensive and may require manpower.MSMA,an arsenate based systemic pesticide,has a very tight window and all the toxicity problems and paperwork associated with chemical pesticide application becomes an impediment. Recently,Integrated Pest Management has been expanded,but still very large losses are recorded in the forests all over the world due to pest attack.In this context,an Ecological Procedure by the treatment of the infested portion of the trees,soil area or timber and structural logs has been developed. The principle of the method is to introduce by the injection or by Evaporative Equipment, a Cryogenic Gas (usually Liquid Nitrogen or other Inert Gases) in the area with pest attack. It results to the lowering temperatures under the survival level of the pests,modified atmosphere with higher content in gas introduced for the pest control,improper to pest metabolism,reduced humidity and the hardening of the trees which increases their resistance against pest attacks.
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