A STUDY ON THE SPATIAL PATTERN OF ALLOTHROMBIUMSP.AND COTTON APHID
食蚜绒螨和棉蚜的分布关系研究

Seven aggregation indices were used to analyze the spatial pattern of the red velvet mite(Allothrombium sp)and cotton aphid(Aphis gossypii G.)in different stages.The pattern dynamics were tested by fuzzy clustering method. Weibull-I distribution and David and Moore's method were used to analyze similarity of the mite and the aphid in time and number, and difference of their spatial pattern.The results showed that.(1)The mite and the aphid had synchronism in time and number.Under the field conditions,the dynamics of parasiting percentage conform to Wei-bull- I distribution.(2)The patterns of the mite and the alatus aphids were apparently different, while the mite and the apterous aphid's were not apparently different,,(3)The aggregation indices were tested,the results showed that the patterns of the mite and the apterous aphids were aggregate, and alatus aphid's were random.(4) The results from the fuzzy clustering analysis were that the parasited alatus aphids had two day's period,The aggregate of the mite and the alatus aphids were similar in early stages,and the apterous aphid's in late stages, and the questions about the natural enemy controlling connection were asked.