Chestnut weevil, a member of the Coleoptera family Curculionidae, is the most serious pest that damages chestnuts. In recent years, it has occurred seriously in chestnut producing areas. Below we will talk about the occurrence patterns of chestnut weevils and the prevention and control methods of chestnut weevils for reference. The occurrence pattern of chestnut weevil

One generation of chestnut weevil occurs every two years, and the mature larvae overwinter in the soil under the canopy. It pupates in the summer, and the pupal period lasts about 20 days. It emerges into an adult in August. After emergence, the adult worms first lurk in the earthen chamber for 5 to 10 days, and then emerge from the ground. Adults are often unearthed in large numbers 1 to 3 days after a rain. They first go to the chestnut tree to feed on the twigs to replenish nutrients. After more than 10 days, they mate and lay eggs. The egg-laying period is in early August, and the peak period is in mid-to-late August.

The larvae feed on the seed kernel immediately after hatching. The damaged fruit in the early stage often falls off early. After the larvae shed the fruit, they go into the soil to make an earthen chamber to overwinter. The larvae that bore into the fruit in the later stage are still in the fruit during the harvest period. After harvesting, The fruits are removed in the accumulation yard and put into the earth to make an earth house to overwinter. Symptoms of chestnut weevil damage

Adults feed on twigs and young fruits, bite a hole in the chestnut pod and lay eggs inside. The larvae cause damage inside the fruit. After the young pod is damaged, It is easy to fall off. In the later stage, the larvae damage the seed kernel, and there are insect feces in the fruit. After the larvae shed the fruit, there are round holes on the seed coat, and the damaged fruit is prone to mold and rot. Methods for preventing and controlling chestnut weevils

① Eliminate overwintering larvae: Harvest chestnuts in time, and pick chestnut orchards cleanly to prevent larvae from entering the soil with the fallen fruits and overwintering; the threshing site is the best If it is a cement floor, if it is land, you can spray 500 times of phoxim emulsifiable concentrate on the ground to kill the larvae that have entered the soil.

② Prevention and control of adult insects: During the adult insect emergence period from July to August, spray pesticides on the trees to kill the adult insects. You can spray 4.5% high-efficiency cypermethrin EC 1500 times, or take advantage of the suspended animation of adults and shake the branches in the morning to collect and kill the fallen adults.

③ Carbon disulfide fumigation: After harvesting, pile up chestnut canes and seal them with thick plastic cloth. When the temperature is 20°C, use 20 ml of carbon disulfide per cubic meter and seal for 20 hours or use 30 grams of methyl bromide per cubic meter. , sealed and fumigated for 30 hours to kill the larvae in the tent.