Studies On Occurence And Control Of Epitrimerus Pyri (Nalepa) In Pear

On the bases of identification and investigation on Epitrimerus pyri (Nalepa), Longxi County, Gansu Province, the dynamics of natural population, the spatial pattern of natural overwintering population were studied,and four insecticides were tested in field.The result was as followes:(1) Epitrimerus pyri (Nalepa) was collected and identificated from pear tree.(2) The dynamics of the population were studied by investigation in field:Its population density increased normally as the temperature and the peak period of the population in June.(3) The spatial patter of the natural overwintering population of Epitrimerus pyri (Nalepa) wasanalysed by calculating seven indices of aggregation parameters of Taylor model and Iwao model. It belonged to aggregated distribution. Theoretical formula for determination of the sampling numberof natural overwintering population was given: (4) To control the pest ,four insecticides were tested in field, all of them had good effects. 0.2% airuochongqing EC,15% pyridaben EC and 10% clofentezine-pyridaben FF 2000-3000 times dilution and 20% meothrin EC 2000-4000 times dilution reached 98% effect.(5) Morphological changed to pear leaves by Epi trimerus pyri (Nalepa), was examined by tissue sectioning. The number and size of spongy tissue cells increased, the tissue of injured parts protruded towards the back of pear leaves. At last, spongy tissue was broken and cells begin to be separate. At the same time, palisade tissue was also influenced.