不同人工干扰条件下枸杞园害虫的风险性评估与防治策略

在农田生物群落害虫亚群落中，成灾性害虫爆发的事件多为群落内部与环境的不稳定因素共同作用的结果.本文建立了枸杞害虫风险评估体系的2亚体系、5方面、14个指标的综合评价系统，并同时运用害虫风险指数法与经验公式法对宁夏不同人工干扰条件下枸杞园主要害虫进行了风险性分析.结果表明：两种方法的分析结果基本一致，自生园枸杞瘿螨、枸杞蚜虫、枸杞木虱为频发性成灾害虫，枸杞负泥虫、枸杞实蝇、枸杞红瘿蚊、枸杞蛀果蛾为偶发性成灾害虫;有机园频发性成灾害虫与自生园一致，枸杞裸蓟马、枸杞红瘿蚊、枸杞蛀果蛾为偶发性成灾害虫;化防园枸杞瘿螨、枸杞蚜虫、枸杞木虱、枸杞裸蓟马为频发性成灾害虫，枸杞红瘿蚊、枸杞蛀果蛾为偶发性成灾害虫.对枸杞园害虫亚群落的分割为最优5分割，分别为萌芽期、盛发Ⅰ期、休眠期、盛发Ⅱ期和衰退期.相关系数矩阵表明，不同人工干扰条件下枸杞园害虫种群动态显著相关，说明不同人工干扰条件下枸杞园害虫种群动态基本一致，每年均有两个建群期，一个指数增长期.综上确定萌芽期中后期至盛发Ⅰ期前期、盛发Ⅰ期中期、休眠期晚期至盛发Ⅱ期前期为最佳防治阶段，是控制害虫的关键时期.

Risk assessment and control strategies of pests in Lycium barbarum fields under different managements.

In the risk assessment of pests, both the community structure and the environmental factors should be considered at the same time, because of their mutu al effects on the outbreak of disaster pests. This paper established a comprehen sive assessment system, including 2 sub-systems, 5 respects, and 14 indices. In the meanwhile, risk assessment indices and experience formula were used to anal yze the risk degree of pests in Lycium barbarum fields under different manag ements. It was found that using risk assessment indices and experience formula c ould obtain similar results. In abandoned field, Aceria palida, Aphis sp., a nd Paratrioza sinica were the frequent disaster pests, Lema decempunctata, Neoceratitis asiatica, Jaapiella sp., and Phthorimaea sp. were the incidental disaster pests, and Psylliodes obscurofaciata and Phthorimaea sp. were general pests. In organic field, the frequent disaster pests were the same species as t hose in abandoned field, while P. indicus, Jaapiella sp. and Phthorimaea sp. were the incidental disaster pests. In chemical control field, A. palida, Aphis sp., P. sinica, and P. indicus were the frequent disaster pests , while Jaapiella sp. and Phthorimaea sp. were the incidental disaster p ests. Optimal 5 separations most fitted the division of pest sub-communities in L. barbarum fields, which were infancy period (from March 28 to April 15), outbreak Ⅰ period (from April 15 to July 18), dormancy period (from July 18 to September 8), outbreak Ⅱ period (from September 8 to October 15), and recession period (after October 15). The matrix of correlation coefficient showed that th e dynamics of pests in L. barbarum fields under different managements were s ignificantly correlated with each other, suggesting that the dynamics of pest po pulations was similar in different L. barbarum fields, which had two populat ion establishment stages and one exponential growth stage in every year. The opt imal controlling stages were from late infancy period to early and middle outbre ak Ⅰ periods, and from late dormancy period to early outbreak Ⅱ period, which were very critical for pest control.