Study On The Biological Characters And Control Efficacy On Crops Spider

Crop tetranychoidea is an important kind ofcrop best. The biologicah control of the crop tetranychoidea in IPM must be stengthen. Stethorus punctilun Weise was studied in this thesis that looked on as an important kind of the natural enemy of the crop tetranychoidea. It was studied in this thesis that included biological characters and control efficacy oncrop tetranychoidea. This study can achieve purpose of cutting down cost, raising economic benefits and improving ecological environment. The results showed:1.The development of stethorus punctilum Weise pass four stages:egg, larve,pupa and adult ladybird . development zero of egg was 14.22℃. Devdlopment zero of adult was 12.74℃. The two peaks of population of stethorus punctilum Weise appeared in crop field during July and August, the population of the former peak was rather large.2.Ability of cole-resistant of stethorus punctilum Weise showed: adult> larva> pupa, adult was chilled at 5℃±1℃ in the refrigerator for 50 days. Larve was chilled in the refrigerator for30 days. Pupa was chilled in the refrigerator for 20 days.3.The starvation endurance ability of stethorus punctilum Weise have about 2.714days, longest for 6 day, short 1 day.4.The harmful action of some pesticide to stethorus punctilum Weise in 24h ,were, The acting force of Dimethoate is strongest to stethorus punctilum Weise,5.Relationship between amount of tetranychoidea fed by stethorus punctilum Weise and population of tetranychoidea showed anegative accelrative curve. The functional reaction equation that the adult ladybirds preyed on tetranychoidea was 1/Na = 0.00503+ 2.0551/N, equation belong to the functional reaction of Holling II phase and the daily maximun amountof the tetranychoidea fed theoretically by the ladybirds was 198.81 tetranychoidea . the ratio between this predator and oite appromiate to l:50-60.because of disturbing of ladybirds of itself, amount of the tetranychoidea fed theoretically by th ladybirds was decrease when density of ladybirds raise.6.Stethorus punctilun Weise can live maximun about 32 days with artificial diets.7.With increasement of population of tetranychoidea, population of stethorus punctilum Weise increase. When population of tetranychoidea increase froml75.28/plant to 970.92/plant, population of stethorus punctilun Weise ahult increase from 0.38/plant to 6.92/plant.