Abstract: Population ecology of Micracanthorkynchina motamurai in Coreius guichenoti in the upper reach of Yangtze River was investigated in the paper.166 Coreius guichenoti caught from May to July,2003 were examined.The results showed that among all the examined fish,the infection rate was 69.88%,the infection intensity was 8.18,and the relative density was 5.72.The female fish were more vulnerable to M.motamurai than the male.The fish with a body length of 4～5.9 cm were the most easily to be infected which drastically affected their relative fatness.The frequency distribution of the parasite was negative binomial distribution in the fish population.The parasite were clustered at the forepart of the intestine which mainly composed of individuals with a length below 5.0 mm.The female parasites were much more than the male.

Key words: Emerald ash borer, Spathius agrili, Woodpecker, Spatial pattern, Ecological control