Common pests of Malus chinensis

Piercing and sucking pests

Apple aphid

Apple aphids overwinter as eggs on branches and inside cracks in the bark, and hatch in spring. The hatched larvae cause damage on leaves and new shoots. When the growth period reaches its peak, winged viviparous females appear in large numbers and move to other plants to cause damage.

Apple Red Mite

This pest also overwinters as eggs. Most of the overwintering eggs are laid on the bud scales of 1 to 2 year old twigs. After mid-June, reproduction accelerates and the number of insects doubles. July every year is the most serious period of damage. The lack of nutrients that harms the crabapple trees causes a large number of adult insects to lay eggs for the winter.

Integrated prevention and control

Prune infested branches at any time, or use tools to scrape off the insect bodies; spray 5% heavy diesel emulsion before the crabapple sprouts to prevent overwintering eggs; protect natural enemies of pests, such as ladybugs, birds, etc.

Leaf-eating pests

Navicula

It overwinters in the soil in the form of pupae. Adults emerge in mid-to-late June and reach their largest number in mid-to-late July. It has a strong phototaxis and prefers to be active at night. It lays eggs on the back of leaves and eats the leaf flesh from the leaf edge inward. It is inactive during the day and prefers to feed in the morning and evening.

Leafroller

The larvae overwinter in silk cocoons at the top of branches, harming the tender leaves of new shoots and affecting their growth. After emerging as adults, they lay eggs on the back of leaves. The larvae harm trees by chewing the tender leaves.

Integrated prevention and control

Prune in winter and completely cut off the damaged treetops; use black light to lure and kill the adult insects as they are phototactic; use natural enemies of pests such as the migratory wasp and the weekly gnawing wasp.