摘要
基于1990—1992年间对杭州市郊区小白菜上萝卜蚜（Lipaphiserysimi）种群的田间抽样调查数据，根据虫口密度（m），将数据归为两组，一组为整个虫口密度范围的数据；另一组为虫口密度≤5头／株范围的数据．每组数据选择不同的数阈值（T），利用每样方不超过T头蚜虫的植株比例（P_T）与种群密度的关系，通过拟合经验公式Ln进行二项式抽样设计．对抽样方差（用MSE估计）、抽样精度（用d估计）进行分析发现，当用整个密度范围的数据进行拟合，且种群处于较高密度（m≥5）时，其理想的T值为10，可用于小白菜上萝卜蚜种群的二项式抽样设计．当用虫口密度m≤5的数据进行拟合时，T＝4时可保证抽样精度，但从实际应用考虑，则不宜用于萝卜蚜的二项式抽样设计．应用本文方法所发展的0—1抽样方法，无论是在整个密度范围还是在密度≤5的范围，都由于产生较大的抽样误差而不宜用于萝卜蚜。
Field sampling the turnip aphid,L.erysimi. on B.campestris ssp.chinensis was carried out in the suburbs of Hangzhou from 1990 to 1992. From the sampling data,mean aphid density (m),variance (s^2) and the proportion of plants with no more than T aphids (P_T),where T is defined as the tally threshold,were calculated.In order to investigate the influence of the range of density on development of binomial sampling plans,two data sets were organized from the sampling data-the first set included the whole range of density and the second set included only the data with m≤5 aphid per plant.For each of the two data sets,the empirical relationships between m and P_T of the aphid were developed for different levels of T using the parameters estimated from the linear regression of ln (m) on ln〔－Ln (P_T)〕. Comparisons of the determination coefficients (r^2),the variance of m estimated from P_T(Var (m)) and the sampling precision (d) were made between different T values.The results suggested a reasonable tally threshold of 10 for L.erysimi when its m≥5.Thus,T＝10 can be recommended to use for developing the binomial sampling plans and monitoring the turnip aphid populations for control decision making under relatively high population densities.For m≤5,T=4 could produce acceptable levels of sampling precision but has no applicability in the field sampling.The results also showed that the conventional binomial sampling (i.e.presence or absence sampling) plans developed in this paper could produced unacceptable low levels of sampling precision and thus could not be used in sampling of this aphid.
出处
《生物数学学报》
CSCD
北大核心
1995年第4期83-90,共8页
Journal of Biomathematics
基金
霍英东教育基金会青年教师基金
国家自然科学基金!88900038
关键词
萝卜蚜
小白菜
虫口密度
二项式抽样设计
Lipaphis erysimi,Brassica campestris ssp.chinensis,Aphid population density,Binomial sampling plans.
