What is the diamondback moth pest of Chinese cabbage and what pesticide is effective?

Morphological characteristics: adult male moths have gray-brown wings and female moths are gray-white; The front wing is a long and narrow dark brown dot, in which the front edge is slightly shallow and the rear edge has yellow-white wavy lines from the base of the wing to the corner. There are three twists and turns in the front edge of the pattern. When it stops, the wings cover the back of the body and are shaped like a roof. The wavy line consists of three rectangular yellow and white spots with kite lines. The hair on the front wing is very long and sticks up like a chicken's tail. The egg is oval, light yellow, slightly flat and smooth. Larvae is spindle-shaped, with slender ends, obvious joints, buttocks extending backward, exceeding ventriloquism, turquoise or grayish white, and brown hair. The pupa begins to turn light green, then grayish brown. It is wrapped in the sparse cocoon of online celebrities. Cocoons are mostly spindle-shaped, and the body of silkworm chrysalis can be seen outside the cocoon.

Life habit and hazard characteristics: Adults glow day and night. The moth overwinters mainly in pupa in the north, but there is no overwintering and mooncrossing in the south. Adults can mate as long as they emerge, and they can mate many times in their lives, with overlapping generations. You can lay eggs after mating 1 ~ 2 days, and the spawning period is 3 ~ 1 1 day. Overhatched larvae often bite the epidermis of leaves, drill the front half in it and feed on mesophyll. Grass-age larvae harm leaves and form transparent spots called "opening the skylight". There are holes or holes in the leaves of 3 ~ 4-year-old larvae. In severe cases, feed the leaves with a net. The concentrated injury of stunts to the heart and lungs. When the larva is frightened, it will twist, retreat and spin down.

Control methods: agricultural control: rational distribution, avoiding annual continuous cropping of cruciferous vegetables in a small scale, and rationally deploying and cultivating early, middle and late-maturing varieties of Chinese cabbage. Biological control: suitable for bacterial insecticides. For example, each gram contains 500~l000 times dilution and 0. 1% detergent of various small golden mushrooms such as insecticidal bacteria, entomogenous fungi 140 and Bt powder containing 1000 billion spores. Chemical control: 50% Bataan wettable powder 1000 ~ 1500 times dilution, 50% Syndion EC 2000 times dilution, 10% insecticidal powder EC 2000 ~ 2500 times dilution, or 50% moth red oil 700 ~/kloc-0.