Symptoms and control techniques of litchi stem borer

Litchi fruit borer is the main pest of longan and litchi. The young shoot, flower ear and fruit were damaged by larva decay, the fruit fell seriously in the young fruit stage, was damaged in the mature stage, the fruit stem was full of insect dung, affected the quality, the tender shoot and flower ear were damaged, the apex withered, affected the growth of new shoots and blossomed and fruited in the following year. The 10 generations of the insect occurred in southern Fujian, and the generations overlapped. The larvae overwintered in the branches, began to pupate at the end of March, damaged branches, flowers and fruits in the early and middle of April, mainly damaged fruit and tender shoots of longan from early August to early September, and damaged litchi and longan shoots from mid-September to early November. Prevention and control methods: 1, combined with control pruning. The winter shoot is an important place for the insect to overwinter. autumn shoots should be cultivated, winter shoots should be trimmed, and spring shoots with more population should be cut off. In February and May to July, the fallen leaves and fruits should be swept away in time, and the insect source should be eliminated. 3. Chemical control: spraying 3 times a year, in litchi and longan from falling flower to young fruit stage, 15 ~ 20 days before fruit ripening and autumn shoot sprouting and leaf spreading stage, and applying pesticide in larva hatching to peak stage. It can also be used to control litchi bug, litchi tip moth, longan Haimai moth, longan horn planthopper and so on. The medicament can be selected as follows: 10% high-efficiency chlorhexol 3000 times, 4.5% Ludan EC 1000 times, 2.5% Kungfu 2500 times, 40.8% Lexben 1000 times, 2.5% enemy killing 2500 times, 20% scavenging 2000 times + 80% dichlorvos 1500 times, 5% cardicarb 1500 times, etc. In order to avoid pits caused by pests, the above chemicals should be used alternately.