What are the control methods for the privet geometrid?

Distribution: distributed in Northeast China, Henan, Jiangsu, Zhejiang; also in Korea, Japan, and the Soviet Union.

Damage: it harms water fir, privet, lilac, water wax, and small wax. The larvae spin silk webs and feed inside them. When the population is high, they form large silk webs that cover the entire tree, eating all the leaves, affecting tree growth and even causing the trees to die.

Morphological characteristics: [Adult] body length 12-15 mm, wingspan 31-40 mm, body and wings white with a silky luster. The outer margin of the wings has 2 pairs of black dots, the outer row between the veins and the inner row on the veins; the forewing has 1 relatively large black spot at the upper end of the discal cell, and 3 black dots on the veins at the wing base. [Egg] oval, length 0.5 mm, light yellow when newly laid, gradually turning rust-red, with a pearly luster. [Larva] body length about 20 mm, head black, ecdysial line light yellowish-brown; body earth-yellow with many irregular black spots, the spots on abdominal segments 1-5 relatively large. [Pupa] body length 18 mm, light yellow, with many black spots.

Life habits: 2 generations a year, overwintering as small larvae on branches; when the temperature is high or at noon on sunny days, the larvae can still feed. In Zhejiang, the larvae become active in early April, spin webs in the canopy and feed voraciously; their feeding range is within the webbed canopy and branches, and they rarely move away. After the leaves inside the web are eaten up, the larvae move away, first spinning a web and then feeding. In mid-May, the larvae mature and pupate on the silk web. Adults emerge from late May to early June, mostly during the day. During the day the adults rest quietly on the silk web but can also move about, and they mate on the silk web. Eggs are mostly laid on the silk web, hanging in strings on the silk web. If the leaves on the canopy and branches below the silk web are eaten up, the adults also fly away from the original silk web to lay eggs on nearby intact branches and leaves, but the adults do not fly very far. The first-generation larvae damage from early July to the end of August, with the most severe damage in early to mid-August; they pupate in mid to late August. The second-generation larvae hatch in early September and gradually overwinter in October.

Control methods: 1. This insect cannot live without its silk web throughout its life, so the silk web can be pulled off to destroy the pupae and eggs. 2. During the larval stage, pull off the silk web and spray 80% dichlorvos emulsifiable concentrate or 90% crystalline trichlorfon at 1000-1500 times dilution, or fumigate with dichlorvos smoke agent.