Cotton cotton

The scientific name Dysdercus cingulatus (Fabricius) is from the order Hemoptera, Rhododendron. Alias ​​from the spotted cotton red dragonfly, two stars red dragonfly. Distributed in Hubei, Fujian, Guangdong, Guangxi, Yunnan, Hainan and Taiwan.

Host cotton and other malvaceous plants, occasionally damaging sugarcane, corn and other grasses, cape gooseberry, soil tobacco and so on.

Injury characteristics, nymphs through the cotton boll shell absorb the developing cottonseed sap, caused by cottonseed and fiber can not fully mature.

Morphological characteristics Adult body length 12 to 18mm, width 3.5-5.5mm. Head, thoracodorsal plate, forewings red; tentacles 4 black, the first quarter base vermilion longer than the second section, 喙 4 red, the fourth half of the end black, extending to the second or third abdominal section . The scutellum is black, and the center of the leather piece has an elliptical black spot with a black belly. The chest and abdomen were red in ventral veins, with white transverse bands with thickened ends only at the posterior borders of each segment. There were arc-shaped white lines on the outside of each foot base segment, and each segment was reddish black. Eggs are about 1.1mm long, oval, yellow, smooth surface. The newly hatched larvae are yellow, turn red after 12 hours, reach the first abdominal section; grow wing buds after 3 years of age, have 3 chloasma spots on the back, 3 white spots on both sides; 5th body length is 8-10 mm, neck White, wing buds reach the first abdominal section, belly color like adults.

Life habits Yunnan is born 2 generations ago, wintering with eggs in the topsoil, and adults and larvae wintering in the earth seam or under cotton litter. Ten days after emergence, females began to mate 1 or 5 times, each time for 60 to 100 hours, individually for up to 12 days. After spawning more than 10 days before spawning, spawning 1-3 times, a generation of 102, a second generation of 79, generally 20-30 a pile, produced in the earth seam or litter or under the rhizosphere soil surface, sometimes produced On cotton boll leaves or cotton wool, egg period 6-7 days. The larvae were 5 instars, and the larvae were about 15 days old. The newly hatched larvae first colonize the cotton plant or weeds in the rhizosphere and transfer them to the young cotton boll. There were two peaks of damage from May to July and from November to November. Adults fly poorly but crawl quickly. The activity temperature is 22-34°C, and it is inactive below 17°C. It is less than o°C and dies in 5 hours. It is higher than 37°C and dies in 3-4 hours. Suitable relative humidity 40-80%. High temperature and low temperature favor the occurrence of this worm. There are natural enemies such as fly, hunting, red insectivorous, and birds.

Control methods (1) Use grain and cotton rotation to cut off the insect food chain. (2) If necessary, spray 90% crystal trichlorfon 900-1000 times, with excellent control effect.