宁夏苜蓿田直条根瘤象分布类型和种群动态

Distribution types and population dynamics of Sitona cylindricollis in alfalfa fields in Ningxia

直条根瘤象(Sitona cylindricollis)是宁夏苜蓿上新发现的一种重要害虫。为明确其田间分布型和种群动态情况,于2020年和2021年5—9月在宁夏惠农区和平罗县的苜蓿田进行发生动态调查及聚集度指标测定。结果表明,5—9月直条根瘤象成虫呈先增后减动态变化,8月份是成虫发生的高峰期。成虫和幼虫在田间均为聚集分布,形成聚集的因素与自身习性和环境因素有关;应用Iwao抽样模型建立了直条根瘤象成虫和幼虫田间理论抽样数公式,提出理论抽样数。明确种群动态规律和田间分布型可为直条根瘤象的预测预报和防治提供科学依据。

Sitona cylindricalis is an important new pest of alfalfa in Ningxia.To clarify its field distribution pattern and population dynamics,we carried out the occurrence dynamics investigation and aggregation index determination in the alfalfa fields of Pingluo and Huinong,Ningxia,from May to September of 2020 and 2021.The results showed that from May to September,the population of S.cylindricalis adults first increased and then decreased,and peaked in August.Adults and larvae were aggregated in the field,and the factors causing aggregation were related to their own habits and environmental factors.The Iwao sampling model was used to establish the theoretical formula for the sampling of adults and larvae of S.cylindricalis in the field,and the theoretical sampling number was proposed.A clear understanding of the population dynamics and field distribution patterns can provide a scientific basis for the prediction,forecasting,and control of S.cylindricalis.