Studies On Biology Characteristic And Control Of Main Pests In Nitraria In Delingha Area

There are three species Nitraria in Qinghai Province, it belongs to Zygophyllceae Nitraria, mainlydistributed in Dulan, Wulan, Delingha of Qaidam Basin. It occupies about250,000hectares and isan important sand-fixation shrub of desert and semi-desert. In recent years, we have observed thatthe damage of some insects on Nitraria vegetation is very serious. So ecological data and biologyare important to understand and determine damage levels, to forecast the population dynamic andappearance of the pest per stage, to develop integrated pest management programs and to constructnew types of control methods. In this thesis, the community of arthropod in Nitraria field inDelingha was investigated; the occurrence, bionomics, the control index and the controltechnology of the major pests were studied. The results were as follows:1. The community of arthropod on Nitraria field in Delingha is composed of2classes,10orders,44families,82species. There are two major pest species: Orgyia antique and Leiometoponsiyrides in this area. There are two species common pests, and carnivorous horsefly, dragonfly andspider are the major natural enemy. A kind of pathogenic microbiology was isolated from thedeath worm, no named.2．Through investigation in field and feeding observation in lab, the biology characteristic andpopulation dynamics of the major pests are known. Orgyia antique depleted the defoliations of theNitraria as larvae; it is a univotine moth in Delingha and occurred seriously in June every year.Itlaid eggs end in late August and overwintering as eggs in the cocoons. Leiometopon siyrides hastwo generation a year in Delingha, the second generation larvae attacked more seriously than thefirst generation, and occurred most seriously in July every year, overwintering as pupae in the soilin late September.3．The losing rate tests showed that: the Orgyia antique’s population density is correlationsignificantly with the wet mass of the Nitraria vegetation, with increasing of the Orgyia antique’sdensity, the yield is reduced obviously. The control index to Orgyia antique is12.53larva/m2, andits Economic Injury Levels (EIL) was4.33%.4．The controlling pest experiment was made to the lavaes of Orgyia antique, several biologicalinsecticides were selected, they are the Abamectin, Leichanjian and Caodue. The result showedthat the Abamectin should be6000to8000times, the Leichanjian and Caodue should be3000times, the emendation effect was100%in7days. When the Abamectin and theAlphacypermethrin, the Abamectin and the Leichanjian, the Abamectin and the Caodue, et al weremixed, the effects are all very well, so they can be used to the pests of the Nitraria.5．The total control strategy to the major pests on the Nitraria shrub in Delingha area wassuggested:1)Known the major pest’s biology characteristic and population dynamic regularity,and the optimum control time;2)Chemical control technology combined with biological controltechnology, selected appropriate biological insecticide to control the insect pest on the Nitrariashrub effectively.