Study On The Relationship Between Occurrence Dynamics And Environmental Factors Of Tetranyclius Truncatiis Ehara

Tetranychus truncatus Ehara is an important pest in Xinjiang crops and forests. The harms ofTetranychus truncatus Ehara result in plant chlorophyll degradation, number reduction and leaf chlorosisturning into sallow, thus diminish the victim leaves’ ability to absorb light energy and photosynthesisstrength. The serious pest mite will lead to plant growth arrest or delay, or even death. This paper takesTetranychus truncatus Ehara as the research object, studies its relationship between occurrence transfer ruleand environmental factors as well as the change rules of leaves green degree, and finally draws thefollowing conclusions.(1)According to the population transfer rules of summer Tetranychus truncatus Ehara and activityrules monitoring of jujube trunk under different intercropping pattern in the Aksu region of Xinjiang. In thethree intercropping mode, Tetranychus truncatus Ehara first appear in the weeds and soil, and start totransfer from the weeds, soil to the jujube and crop in late June. In early July, the population amount ofTetranychus truncatus Ehara on jujube grows rapidly, and peak in late July to early August. In late August,Tetranychus truncatus Ehara gradually transfers from jujube to soil and weeds, and prepares to overwinterin the soil.(2) In summer, Tetranychus truncatus Ehara population is aggregated distribution in the jujube treecanopy from the vertical direction and other different directions, and basic component of its distribution isindividual group. In early July, Tetranychus truncatus Ehara population is highly aggregated in the jujubetree canopy from the vertical direction and other different directions. After the mid-July, aggregationstrength tends to stabilize, and aggregation from all directions and different height is relatively close. Ofthis, aggregation strength from the vertical direction lower layer>upper>middle layer, and aggregationstrength from different directions is in the south> east>west> north.(3) There is close relationship between population amount changes of and average temperature,relative air humidity, sunshine durations and other meteorological factors in the Aksu region. According tothe stepwise regression analysis, population amount changes of jujube Tetranychus truncatus Ehara aremainly results of five meteorological factors of average temperature, relative air humidity, minimumtemperature, maximum temperature and sunshine durations. The analysis shows that the changes of averagetemperature, relative air humidity and sunshine durations have the largest direct impacts on jujubeTetranychus truncatus Ehara population amount changes. Other meteorological factors mainly have indirectimpacts on the population dynamics of jujube Tetranychus truncatus Ehara through the averagetemperature. According to the multiple regression equation between the Tetranychus truncatus Eharapopulation amount changes and main meteorological factors, the comparison of measured Tetranychustruncatus Ehara population amount changes and predicted simulation value shows that there is closerelationship between the measured population amount and predicted population amount, which providesscientific basis for prevention and control time of Tetranychus Truncatus Ehara.(4) The jujube Tetranychus truncatus Ehara population amount changes have a negative correlationwith leaves SPAD value. When Tetranychus truncatus Ehara population density reaches to over20pestsper leaf, and the jujube leaves SPAD value is20-30, causing the most serious harm to jujube chlorophyll;when Tetranychus truncatus Ehara population density to10-20pests per leaf, the jujube leaves SPAD valueis30-40, causing serious harm as compared with the former.