Studies On The Biology And Ecology Of Aceria Litchii(Keifer)

Experiments were conducted to study the harming characteristics of Aceria litchii. The experiment included five aspects as follows: the impacting phenomena, population dynamics of A. litchii and Amblyseius spp., the life table of A. litchii experimental population, predation of A. largoensis to A. litchii, Bioassay of toxicity of three insecticides on A. litchii,The impacting phenomena included four aspects as follows:colour change of gall, observation of gall microstructure, mensuration of chlorophyll contents in the impacted litchi leaves and orientation of A. litchii in litchi.The observation showed the process of gall colour chang was as follows: flavo-green articulate fascia pallid villus flavo-green insect gall helveolous insect gall yellow insect gall yellow brown insect gall luteofuscus insect gall nicotianus insect gall. The observation of microstructure of impacted leaves showed that the change and below epidermal, sponge tissue, pale tissue and upper epidermal lost in the insect gall leaves .These phenomena showed that the experiment of insect gall and proved that the insect gall had greatly destroyed the inner structure of litchi leaves.The mensuration of the chlorophyll content showed that the chlorophyll content in litchi leaves decreased with A. litchii density increased. The chlorophyll content in litchi leaves decreased with the harmting continuing. The result showed that the chlorophyll content had the decreasing trend with the harming enhancing. Thedecreasing stopped after forty days.Through the investigation of azimuthal of A. litchii in litchi we found:There were extremely significant differences among the species of litchi in the situation impacted by A. litchii. The heavily impacted varieties were " no 5 "and "no 19". There were no differences in the azimuthal of A. litchii's distribution in canopy of trees and among different period impacted leaves . There were significant differences in level of the tree which were impacted by A. litchii.The study of the field population dynamics of A.litchii and Amblyseius spp. showed that the result of the Gray Sequence of Four Ecological Factors to A. litchii showed that the gray sequence of them to nymphs is rainfall >humidity >temperature >natural enemy, to adults, humidity >rainfall >temperature> natural enemy , and to the population is rainfall > humidity >temperature >natural enemy.The observation of A.litchii raised indoors showed that A.litchii had the characteristics of hibernation, aestivation, minus taxis to water and light.A. litchii experimental population was stablished at constant temperature 25 "C,illumination time of 12 hours one day and humidity 80-85%. The result indicated that the value of the innate capacity of increase was 0.167161 on litchi leaves ,the period of doubling population was 4.146584 days.The result of two curves showed that the ability of procreation was the highest in the twelfth day, then became reduced.The result of the microstructure of galls showed that this trend seriously influenced the processing of photosynthesis, above all the leaves were of the nutrition organs of litchii, the inference was given that this trend would greatly affect the quality and quantity of litchii.The result of predacious function .density interference effect and numberical response showed that the predacious function response of Amblyseius largosensis. adults was of the Holling II type, the interference effect of the population density ofthe predator to its preying activity was significant, and as its density of itself increased the daily preying capacity decreased. The upper limit of the daily preying capacity for Aceria litchii was 47.5 adults percent day at constent temperature of 25 and humidity of 80-85%. Thus the correlation between the prey density with the average daily oviposition can be described with logistic model.The result of Bioassay of toxicity of three insecticides showed that there was significant defference among the tocicity to population of three districts. The ratio of LC50 to pyri...