Boat-shaped caterpillars, also known as apple Tenzo moths, tail-lifting insects, etc., are mainly harmful to cherry, plum, apricot, apple, pear and other fruit trees.
First, the morphological characteristics of boat-shaped caterpillars
1. Adult insects. The female moth is 30 mm long and has a wingspan of 50 mm, and the male moth is small, yellowish-white, compound eyes black, and brown antennae. The forewings are silvery white with a slightly yellowish tinge , with a silvery-gray nearly oval spot near the center of the base.
2. Eggs. Spherical in shape, about 1 mm in diameter, pale green at the time of initial birth, grayish-brown when near hatching, often dozens of grains neatly arranged in blocks, produced on the back of the leaves.
3. Larvae. The body is 50 to 55 mm long, the back of the chest and abdomen is purple-black, the sides are purple and red with yellow longitudinal stripes, the ventral surface is purple-red, and each segment has long yellow-white hairs. At rest, the ends of the larvae's head and tail are cocked like a boat. The initial hatching larvae are earthy yellow and turn purple-red after 2 years.
4. Pupae. The body is about 23 mm long, dark reddish-brown, and the whole is densely carved.
Second, the boat-shaped caterpillar is a symptom of pest
The larvae feed on the leaves, the young larvae bite the leaf flesh, and the damaged leaves are only the epidermis and veins, which are reticulated; the larvae bite the whole leaf slightly, leaving only the petiole, and when it is severe, the whole leaf leaves can be eaten.
Third, the occurrence of boat-shaped caterpillars
It occurs in one generation a year and overwinters in a deep layer of soil 7 cm under the tree, and if the surface is hard, it overwinters in dry grass, leaves, soil or stones. Feathering from early July to mid-August of the following year, spawning 1 to 3 days after tailing, eggs laying on the leaf back, egg stage 7 to 8 days, the larvae cluster on the leaf back before the third instar, feeding during the day and night, the cluster of stationary larvae neatly arranged along the leaf margin, head and tail upturned, when disturbed by swarms of spit and drooping. After 3 years of age, it is gradually dispersed to eat. In September, the old mature larvae climb down the trunk of the tree and enter the soil to pupate for the winter.
Fourth, the control method of boat-shaped caterpillar
1-3 instar larvae are concentrated in the pest stage of removing insect leaves or shaking off larvae. Spray 20% cypermethrin emulsion 2000 times liquid, or 2.5% cypermethrin emulsion 2500 times liquid to the insect swarm, and young larvae can be controlled with urea no. 3.