What are the control methods for tea tussock moth in tea gardens?

The tea tussock moth, also known as the tea yellow tussock moth and the head-swaying worm, belongs to the family Lymantriidae of the order Lepidoptera. It is distributed in every tea-producing province nationwide and is an important pest in China's tea regions. It mainly damages tea leaves and can also damage oil tea, citrus and others. Young larvae bite and feed on old tea leaves, leaving a semi-transparent membrane, and later bite young shoots and mature leaves, leaving notches. The larvae feed in groups, often dozens to hundreds gathering on the underside of leaves to feed. When the outbreak is severe, tea leaves are eaten almost completely.

Morphological characteristics: The adult is about 10 mm long with a wingspan of about 28 mm. The female moth is slightly larger, with a yellow-brown body and wings; the male moth is slightly smaller and brown. There are 2 pale yellow transverse bands in the middle of the forewing, and 2 black dots within the pale yellow area at the wing tip. The end of the female moth's body has a yellow hair tuft. Eggs are laid in masses; the egg mass is oval and covered with yellow fuzz. The mature larva is about 20 mm long and yellow-brown. The three thoracic segments are slightly smaller. Each body segment has 8 yellow (early stage) or black hair tubercles, bearing yellow-brown venomous hairs. The whole body is also densely covered with yellow venomous hairs of uneven length. The pupa is yellow-brown, about 9 mm long, enclosed in a thin, earth-yellow silken cocoon about 13 mm long.

Occurrence pattern: It is multivoltine, and the number of generations varies from place to place. In Hunan it occurs 3 generations a year and overwinters as egg masses on the underside of old leaves. The larval damage periods of each generation are respectively from April to May, June to July, and August to October. Generally, the spring and autumn generations are the most severe. After the larvae mature, they form cocoons and pupate in the soil beneath the fallen leaves at the base of the tea bush.

Control methods

(1) From November each year to April of the following year, remove the overwintering egg masses by hand.

(2) Remove the groups of newly hatched larvae of each generation.

(3) During the adult occurrence period, use light traps to attract moths, or use sex pheromones to trap and kill male moths.

(4) In combination with cultivation, bury the cocooned pupae deep in the soil.

(5) Biological control. Use the tea tussock moth black egg wasp and the Apanteles wasp to control egg masses and larvae. During the larval stage, spray Bacillus thuringiensis or tea tussock moth nuclear polyhedrosis virus.

(6) Chemical control. During the larval stage, spray 90% trichlorfon, 80% dichlorvos, 50% malathion, 50% fenitrothion, and 50% phoxim each at 1000-1500 times dilution, or 10% permethrin, 20% fenvalerate, and 2.5% deltamethrin each at 5000-6000 times dilution, or 25% diflubenzuron at 1000 times dilution.