| Through observing the fecundity,incubation conditions and female adults position on leaves of out-hibernate hawthorn spider mites under laboratory conditions,and establishing the population in single leaf, then analyzing the relationship between leaf impact and population dynamics. The results indicates that:Mostly there was one female adult on the back of single leaf during out-hibernate period,and there were two or more on some leaves back,most of them distributed leaf base area. When several mites existed, they maybe transfered to the front of leaves. After the hibernation, female adults could immediately enter spawning condition when suitable environmental condition come. Affected by cold weather, its fecundity was low. Took later period nymphs on the back of leaves in the quiescent, its incubation rate were high, mortality rate after incubation were low, then located and eat the nearest food. After incubation, the distribution position of female adults were leaf base> middle>tip,their number difference was significant. In same period, the mites mortality number arranged for the middle>upper>lower, and the differences between various parts reached a significant level, which indicated that under the test conditions,hawthorn spider mite prefered tender part and safe environment .In laboratory conditions, through designing different initial mite numbers in single apple leaf for 1 mite / leaf, 3 mites / leaf, 5 mites/ leaf, then observed leaves change,mites reproduction and population diffusion process, finally the development from individual to population and the process which lead whole apple leaves to dry were recorded.Result showed that hawthorn spider mites occurred two full generations with the temperature of 28.90±3.60℃and relative humidity of 57.69±20.31% during 35 days under indoor conditions.The more initial mites number were took in single leaf,the faster population expanded, and more serious damage appeared on apple seedlings.It just took 20.4±1.1 days to destroy the plant when inoculated 5 mites in single leaf.The key of prevention was low initial number and controlled them earlier before obvious spot happened in leaves. People should pay close attention to the propagation dynamic when reached 5 mites in single leaf.Compared mites numbers of each type distribution of apple seedlings different parts, this study found that the distribution of the female adults was upper>lower>middle, they prefered more tender upper leaves feeding,the distribution of ovum was central>upper>lower,which showed hawthorn spider mite reproducted more eggs in the middle of seedlings. The initial stage of inoculation,female adults m*/ m<1, it was the uniform distribution;then mites capacity increased when the growing season reached, it was m*/m> 1,displayed the aggregate distribution.The more initial amount of mites,the higher state of aggregation,when the leaves collapsed,nutritional deficiencies after the aggregation of leaves,a large number of mites left leaves and found new food sources .From individual to population,hawthorn spider mites had an alarming growth rate,which was very difficult to control。Mite initial number on the leaves related to disaster level and temperature and humidity closely, food quality and quantity also had an important impact.Because of that, the key of orchard management was initial number control,when the fall victim suffer injury was not very serious people could use some non-chemical measures immediately。...
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