Effect of agronomic measures on population dynamics of sweet potato stem nematode (Ditylenchus destructo)
几种不同农艺措施对土壤甘薯茎线虫种群动态的影响

The effects of agronomic measures on the dynamics of Ditylenchus destructor population was investigated at a 5-continuous-year sweet potato experimental site. The results show that the population of D. destructor for treatments with crop rotation, crop rotation and film mulch, and crop rotation and film mulch with resistant plant variety is lower than that of the control. The agronomic measures of crop rotation, crop rotation and film mulch, and crop rotation and film mulch with resistant plant variety decreases D. destructors population in the soil by 37.24%, 49.45% and 54.33%, and yield of sweet potato remarkably increases by 130.34%, 132.74% and 161.73% respectively. However, cover crops like rye do not significantly reduce D. destructor population. Under cover crops,D. destructors average population in the soil decreases only by 23.26% whereas sweet potato yield remarkably increases by 83.26%. Correlation analysis shows that D. destructors average population in the soil negatively correlates with yield increase, while it positively correlates with morbidity and disease index of sweet potato, with correlation coefficients of -0.978 9, 0.958 1 and 0.975 4 respectively. Treatment of crop rotation and film mulch with resistant plant variety is recommended since it inhibit D. destructor population growth most significant.