1 Influences and Characteristics of Rain and Snow Freezing Disasters on Forest Diseases and Insect Pests
In general, for insects that overwinter in a variety of relatively bare ways, such as leaf-eating pests, continuous low temperatures and snow and ice freezing will reduce the survival base of overwintering pests, reducing the number of populations in the current year; but the occurrence and outbreak of secondary pests and diseases It is extremely beneficial that the broken branches of forests in large areas can easily cause a lot of wounds and lead to a sharp decline in the growth potential of forest trees. Many wounds are the infestation sites of many kinds of bacteria. The rapid decline in tree vigor can also trigger the intrusion of some decaying bacteria. Therefore, the severe occurrence of all kinds of weak parasitic diseases will be revealed in the year; and the secondary forest drilling performance Insects (such as various species of longhorned cattle, small clams, and giardia, etc.) mainly invade trees and forests with debilitating trees. Disasters will have an appropriate lag in their impact. Populations will generally increase sharply within 2-3 years after the disaster. It has become a base for continued occurrence of pests and diseases, resulting in greater follow-up disasters and vicious circles.
2 Principles and technical points of forest pest control
2.1 Disaster Investigation and Classification of Damage Levels
In conjunction with other disaster relief measures, disaster investigations are immediately conducted. Based on the specific conditions of dehydration, broken tipping, freezing, freezing, etc., light, medium, and heavy damage standards and damage classifications are proposed for different forest species, tree species, and forest age. .
2.2 Prevention and Control Measures of Key Forest Trees
2.2.1 Pine forest: loosening or tilting the forest to straighten and cultivate the soil; timely cleaning or dying of the forest, using a fairly standard seedlings for replanting; timely and moderate light cutting of the broken and frozen collaterals. Smooth and brush the wound with Bordeaux mixture or lime sulfur. The main technical measures for mature forests include cutting off branches, breaking off trees, lodging forest trees, tilting the trees to correct or cut trees, and clearing forest lands in time; and renovating forest lands with large gaps and forming forest gaps.
2.2.2 Economic forests: Freezing damage provides a good environmental condition for the epidemic of chestnut branch diseases. After the snow is cleared, the litter of the chestnut garden should be cleared in time and burned in a concentrated manner. After clearing the garden, spraying the Bordeaux mixture or 50% carbendazim from 800 to 1000 times on the trees and the ground surface.