苜蓿蚜虫是苜蓿(Medicago sativa)田的重要害虫之一.为了明确苜蓿蚜虫在青岛地区苜蓿田的空间分布格局和种群动态规律,为综合防治提供依据,2013年对青岛地区苜蓿蚜虫混合种群进行了田间系统调查,运用聚集指标法分析了蚜虫在不同时期的空间分布型,利用最优分割法对蚜虫种群田间动态进行了划分.结果表明,青岛苜蓿田蚜虫在田间发生有两个高峰期,分别在5月下旬和10月下旬;在种群密度较高时均为聚集分布,且聚集强度随蚜虫密度的上升而下降;采用最优分割法将苜蓿蚜虫种群动态划分为7个阶段,即发生初期(4月6日之前)、发展期(4月14日-5月11日)、快速增长期(5月18日-5月25日)、衰退期(6月1日-6月8日)、再次发生初期(6月8日-9月15日)、再次发展期(9月22日-10月2日)、再次快速增长期(10月7日-10月27日),并对每个阶段的特点及影响因素进行了分析.因此,苜蓿蚜虫在青岛地区苜蓿田中的分布以聚集分布为主,其发生有两个高峰期,防治时期应以种群快速增长期的5月上旬和10月上旬为主.%Aphids are one kind of serious insect pest in alfalfa fields.In order to clarify the spatial distribution pattern and population dynamics of alfalfa aphids in Qingdao,and provide a basis for integrated management, aphid population dynamics were analyzed in a Qingdao alfalfa field in 2013.We studied spatial distribution pat-tern and optimal partition using aggregation index method and optimal partition method,respectively.The re-sults showed that the aphid population had two annual peak occurrences:late May and late October.The popu-lation demonstrated aggregate distribution when at a higher density,and the aggregation intensity decreased with an increase in population density.The population dynamics could be divided into seven periods using the optimal partition method:initial stage (before April 6);developing stage (April 14 to May 11);quick-increase stage (May 18-25);decline stage (June 1-8);secondary initial stage (June 8 to September 15);secondary developing stage (September 22 to October 2);and secondary quick-increase stage (October 7-27).We dis-cussed the characteristics and impact factors of each stage.Alfalfa aphids in Qingdao demonstrated aggregate distribution and the population experienced two peaks.The suitable control stages are early May and early Oc-tober.
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