A STUDY ON SAMPLING TECHNIQUES FOR DENDROLIMUS TABULAEFORMIS LARVAE
油松毛虫(Dendrolimus labulaeformis)幼虫抽样技术的研究

Under condition that the statical and dynamical patterns of Dendrolimus tabulae-formis larvae were tested, have been studies conducted systematically on the tree sampling, ring sampling and branch sampling. Based on the characteristics of the vertical distribution of the larvae on each ring of Chinese pine, it was found that tree sampling is simplified to ring sampling by cresting ring regression models. According to speciality of the larvae feeding mainly biennial pineneedle. the ring sampling was also fuither simplified to branch sampling by creating branch regression models. The results are as foliows.(1) the forecasting precisions of ring regression models are generally 91-98% and those of branch regression models are mostly more than 91%; (2) the efficiency of ring sampling could be raised to 6 times more than that of tree sampling while the difficiency of branch sampling could be further raised to 1.5 times more than that of ring sampling; (3) the sampling cost is 0.2 RMB Yuan for each tree sampling, 0.16 RMB Yuan for each ring sampling, and 0.032 RMB Yuan for each branch sampling.