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(2) Morphological characteristics Adults: About 1 mm in length, both males and females have wings, and the whole body and wings are covered with white wax powder.
Egg: elliptical, approximately 0.21 mm long, approximately 0.09 mm wide, with a small handle 0.12 mm long at the end, yellowish at the time of first production, and dark brown at the end.
Larvae: oval, flat, 3 in all. Body length increases with age, ranging from 0.29 to 0.50 mm.
蛹: 0.7 to 0.8 mm in length, oval, flattened, slightly taller in the center, yellowish-brown, with 5 to 8 pairs of waxes on the back of the body.
(3) Habits of life Whitefly can not overwinter in the open field. In the protected area, all insects can safely pass through the winter, and the various forms of insects are used to protect the zucchini. The spring is gradually transferred to the open ground, and it is destructed by falling temperatures in the autumn and wintering in the greenhouse.
Whitefly adults have strong yellow tropism, are not good at flying, and have slow outward migration. Like to cluster on the back of the upper leaves of the plant and spawn on young leaves. Therefore, in the distribution of insects on the plants, the uppermost young leaves are formed with adult and early-producing pale yellow eggs, and the lower leaves become mostly black eggs, and the lower part is mostly young larvae. , old age nymphs, the most lower part of the crickets. The eggs are arranged in a ring or in spawns during spawning. When females reproduce, sexual reproduction generally produces females, and most females produce parthenogenetic males.
After hatching, the larvae first crawl on the back of the leaves for several hours. After finding suitable feeding sites, the larvae are fixed on the back of the leaves and sucked and sucked. The larvae were 3rd instar, and the 3rd instar larvae became pupa after molting.
(4) Occurrence conditions Whitefly development, adult life, and spawning are closely related to temperature. The optimum temperature for adult activity was 25-30°C, and the activity of adults decreased significantly when the temperature reached 40.5°C. The lowest egg development temperature is 7.2°C. Larvae have weak cold resistance. At 24°C, the adult period was 15 to 17 days, the egg period was 7 days, the larval period was 8 days, and the flood period was 6 days.
(5) Control methods Whitefly has a wide host range, rapid reproduction, multiple transmission routes, strong drug resistance, overlapping generations, and difficulty in control.
Whitefly found in production should be eliminated immediately. The commonly used agents are: 20% cypermethrin EC 5000x, 2.5% deltamethrin EC 2000 to 3000x, 10% PCP 2000x, 50% DIVP 1000x, 40% Dimethoate EC 1000 times, 40% Acetochlor EC 1000 times, 20% Trichloromethane EC 1000 times, 25% ACCU 1000 times, 2.5% KF 6000 times, 20% FC Lee Emulsion 2000 times, 10% Puercitrin EC 1000 times, continuous spray 3 to 5 times, alternating medication.
Yellow plates were used to seduce adult insects, and the adults were used to yellow the tropism. The orange-colored plates were coated with No. 10 engine oil to trap and kill, and according to the number of insects, orange yellow plates were set.
Artificial grasshoppers were released, and a grass-roached worm preyed on 172 white-flyers. The artificial release of the citron wasp and the larva was mainly spawned in the larvae and pupa of the whitefly, causing the whitefly larvae and crickets to die in 8 to 9 days.
Condition of occurrence of white squash of courgette
(1) Injury characteristics White pheasant whitefly is a member of the order Homoptera Melanoptera, a polyphagous sucking pest. The sap of its larvae and adult needles sucks the sap of the zucchini plant, resulting in chlorosis, wilting, and death of the leaves. At the same time, the adults and larvae can also discharge a lot of honeydew, causing coal pollution, contaminating the leaves and melons, and affecting the photosynthetic. Role, reduce product quality, and spread viral disease.