Key Points to Know About Pest and Disease Control During the Dormant Period of Cedar

When cedar enters its dormant period, how should pest and disease control be carried out?

Treating bark: In early winter or early spring, scrape off the old loose bark, diseased bark, and insect-bored bark from the trunk, large branches, and branch forks, then burn or bury them deep.

Cultivating the forest soil: Cultivating the forest soil before freezing not only loosens the soil and preserves moisture, accumulates rain and snow, and promotes root growth, but also turns residual dead branches and fallen leaves into the soil. At the same time, it turns overwintering pests in the soil to the surface, where they are preyed upon by natural enemies or freeze to death.

Clearing dead branches and fallen leaves: After cedar drops its leaves, promptly sweep up diseased and pest-infested dead branches, fallen leaves, and weeds and bury them deep or burn them in a centralized manner, which helps reduce the overwintering numbers of pathogens and pests.

Whitewashing tree trunks: After cedar drops its leaves, whitewashing the trunk and the base of large branches with whitewash can eliminate pests and diseases overwintering on the trunk and can prevent sunscald and freeze damage. The whitewash can be prepared with 25 parts water, 10 parts quicklime, 1 part lime sulfur mixture, 1 part salt, and a small amount of animal oil.

Spraying for control: After cedar drops its leaves and before bud break, spray once each time with 5 degrees Baume lime sulfur mixture plus 200-fold sodium pentachlorophenate solution, which has a significant effect on eliminating overwintering pathogens and insect eggs and reducing pest and disease damage the following year.