Study On The Occurrence And Government Of Salix Integra Insect Pests In The Low-lying Areas Along The Huai River In Anhui

The dynamics of arthropod communities in Salix integra Thunb. fields and the interaction of main pests with their natural enemies were studied though systematic investigation in the stages of growth and storage of S. integra in Huoqiu and Funan of Anhui, and the regularity of outbreak and chemical control technology of Rhbdophaga salics Schrank and Heterobostrychus hamatipennis Lesne. were studied to provide theory foundation for S. integra production safety. The primary results are as follows:1The investigation of the kinds of the main pests and their natural enemies of S. integra in the periods of growth and storageAccroding to the investigation in2009, there are10orders,47families and98species in low-lying areas along the Huai River in West Anhui, including35families and79species of insect pests, and12families and19species of predatory enemies.The results showed that:the main pests were Rhbdophaga salics Schrank, Plagiodera versicolora, Altica weisei Jacob son, Earias pudicana pupillana Staudinger, Spodoptera exigua Hubner and Phylloxerina capreae Borner. The most important insect pest in S. integra growth period was R. salics. And the most important insect pest in S.integra storage period was Heterobostrychus hamatipennis Lesne.2Biological characteristics of R. salicsR. salics damaged as larvae. The adult longevity was1-3d and non-feeding. The insect spawned in the burgeon. More than10larvae often gathered and formed a gall. The larvae sucked juice in the gall and made the branch furcation.This insect might have3-4generations in the low-lying areas along the Huai River in West Anhui. The larva and pupa overwintered in the galls of damaged wickers in the current year. Overwintering larvae and pupa start to pupate and emergence at the end of March in the next year. The eclosion prosopon might spawn at the same day. The spawn stage4-6d, the larval stage20-25d, the pupal stage10-12d, the duration of a generation were normally in35-40d. Moreover, the larva had the characteristics of diapauses from the second generation.3Indoor toxicity and field efficacy of four insecticides against the larva of R. salicsIndoor toxicity and field efficacy were tested respectively with dipping and spraying methods to determine the efficacy of four kinds of insecticides in controlling the larva of R. salics.20%Acetamiprid SP had the most significant toxic effect on the larva. Its toxicity index was1995.43and19.95times of that of48%Chlorpyrifos EC, which was used as a regular pharmacy in the local.20%Acetamiprid SP,70%Imidacloprid WDG and48%Chlorpyrifos EC exhibited better control efficacy in the field.3days after spraying, the corrected efficacies were60.27%,54.80%and40.83%, respectively.7days after spraying, the corrected efficacies were respectively79.50%,70.71%and58.07%.30days after spraying, the seedling protecting effects were59.74%,50.65%and46.75%respectively. In actual use,20%Acetamiprid SP,70%Imidacloprid WDG and48%Chlorpyrifos EC should be selected to spray at300g/hm2,150g/hm2and1500ml/hm2, respectively. The three insecticides must be used alternately to postpone the appearance of insecticide resistance of R. salics.4Biological characteristics of H. hamatipennisH. hamatipennis is one of the important bush borers in the tropics and sub-tropical regions. The host range is widespread. Both larva and adult can damage. There were some circular holes on the damaged wickers. And the wickers got lighter and easy to break off. The larva had3ages and looked like grub. The larva would huddle in the shape of a ball after being touched. The minor details of abdomen of pupa was smaller and narrower. And it could sway up and down after being touched. The adult longevity was45-62d. The adult could withstand high temperature and drought. The adult often shifted to the new host when night falls.H. hamatipennis might have2generations a year in this area, and matured larva overwintered in the infested wickers. The overwintered larva pupates in late April next year. The pupal stage is10～14days. The adult appeared massively in the last fifteen days of May. The longevity of the overwintering generation could reach about60d. This generation ended in the middle of July. The egg of first generation emerged in late June, and this stage was7～10d. the first generation larva emerged Early in July. The stage of the first generation larva was longer, about55～60d. The first generation larva started pupa early in August. The adult appeared massively in the last fifteen days of August. This generation ended in late September. In the middle of September, larva of the second generation emerged. The second generation Pupa emerged early in October. The adult appeared massively in the middle of October. The stage of this generation adult was shorter, about28～35d. This generation spawned in the middle of October and the larva emerged about ten days later. In the middle of November, the larva got into overwintering state. And the overwintering larva would recover the next year. 5Fumigation efficacy of two insecticides against H. hamatipennisThe fumigation efficacy of two kinds of insecticides against H. hamatipennis were tested. Fumigating on the wickers, the results showed that, the efficacy of56%phosphate aluminum was better. Among6g/m3,9g/m3and18g/m3three doses,9g/m3was best,72h after fumigation, the mortality of different states could achieve100%; the efficacy of dichlorvos was poorer, in the treatments at0.5ml/m3,1ml/m3and2ml/m3, the corrected mortality could not achieve30%at72h after fumigation. Fumigating on the naked insects, the results showed that efficacy were different on different states.24h after fumigating at9g/m3phosphate aluminum, the corrected mortality of larva, adult and pupa were respectively85.72%,73.33%and64.29%. The larvae were more sensitive to phosphine than any other states. Therefore, in order to achieve the best efficacy, fumigation with phosphate aluminum must focus on the stage of recovery of overwintering generation larvae, in March and April.