What are the control measures of tea caterpillar? What's the pattern of occurrence?

Tea caterpillar (Dendrolimus punctatus) is an important pest in Chinese tea area. it is an insect of the genus Lepidoptera in the family Lepidoptera, also known as tea yellow moth, swinging head worm and so on. Tea caterpillar is distributed in all tea-producing provinces in China, mainly harming tea, oil tea, citrus and so on. When it is serious, what are the control measures for tea caterpillar? What's the pattern of occurrence? The following gives you a detailed introduction.

1. Occurrence regularity of tea caterpillar

The adult of tea caterpillar is about 10 mm long and has a wingspan of about 28 mm. The female moth is slightly larger with yellowish-brown wings, while the male moth is slightly smaller and yellowish brown. There are two yellowish stripes in the middle of the forewing and two black spots in the yellowish area of the wingtip. There are yellow hair clusters at the end of the female moth. The eggs are laid in blocks, the egg blocks are oval and covered with yellow hairs. The mature larva is about 20 mm long and yellowish brown. The three segments of the chest are a little smaller. There are 8 yellow (Prophase) or black hairy tumors in each segment, with yellow-brown poisonous hairs on them. All are also densely covered with yellow poisonous hairs of uneven length. The pupa is yellowish brown, about 9 mm long, with a thin yellow silk cocoon outside, and the cocoon is about 13 mm long.

The occurrence regularity of tea caterpillar is multi-generational, and the occurrence algebra is different in different places. There are three generations a year in Hunan, overwintering with egg blocks on the back of the old leaves. The damage periods of larvae of each generation were from April to May, June to July and August to October, respectively. It usually occurs heavily in spring and autumn. After maturing, the larvae formed cocoons and pupated under the surface of deciduous soil in the rhizosphere of tea bushes. The female moth lays eggs on the back of the old leaves. The larvae were clustered at the 7th instar and had strong clustering before the 3rd instar. Tens to hundreds of larvae often gathered on the back of the leaves to feed on the lower epidermis and mesophyll, leaving the upper epidermis in the shape of translucent yellowish green film. After 3 years old, it began to disperse into groups and became harmful, and the bite of the leaves showed a lack of engraving. The larvae mature and pupate under the litter in the rhizosphere of tea bushes or in shallow soil. Adults have phototaxis.

II. Prevention and control measures

The main results are as follows: (1) from November to April of the following year, the overwintering eggs are removed manually.

(2) the newly hatched larvae of each generation were removed.

(3) during the occurrence of adults, light lights to trap moths, or sex hormones are used to trap and kill males.

(4) combined with ploughing deep cocoon pupae.

(5) Biological control: using tea caterpillar black egg wasp and cocoon wasp to control egg mass and larva. Spraying Bacillus thuringiensis or Dendrolimus punctatus nuclear polyhedrosis virus in larval stage.

(6) Pesticide control: spraying 90% trichlorfon, 80% dichlorvos, 50% malathion, 50% fenitrothion, 50% chlorophos, or 10% dichlorophenyl ether cheese, 20% fenpropathrin, 2.5% deltamethrin, or 1000 times of 25% gills.