寄主生境与核桃长足蟓发生的关系

运用系统调查与田间实验相结合的手段,对核桃长足蟓与寄主生境的关系进行了研究。结果表明,(1)寄主生境的阴、阳水平,尤其是树冠生境的遮阳度、地面郁蔽度及地表粗糙度与核桃长足蟓种群发生量呈极显著正相关性,而与海拔高度呈极显著负相关性。(2)阳光直射地面落果可杀伤果内82.5%~87.2%的幼虫;蚂蚁可取食果内19.5%的幼虫,成为第二大自然种群控制因子,果实上产卵孔封口损伤是蚂蚁取食幼虫的直接原因。(3)在自然条件下核桃长足蟓呈聚集型分布,且聚集的原因与个体生物学特性、个体对种群的依赖性和寄主分布有关;幼虫期多雨、连阴的年份成虫种群数量增多;暖冬年份,种群越冬损失率低,翌年果实受害严重;少雨、多光的阳性气候和冬寒低温限制了种群地理分布。核桃长足蟓的最佳防治方法是:处理有虫核桃树冠下地面,以利于阳光照射落果,再配合拣拾郁蔽、多杂草处植株的落果。

Wlnut habitat and Alcidodes juglaus incidence

The relation between walnut habitat and Alcidodes juglaus Chao incidence was studied by combined field investigation and experiment. The results showed that the varied shades of walnut habitat, especially sunshade below walnut canopy,extremely significantly and positively correlated with Alcidodes juglaus Chao population;direct sunshine on fallen walnut fruits on ground could kill 82.5%-87.2% larva inside walnut fruits and 19.5% larva could be spreyed by ants that got inside walnut fruits by invading them through ant-bored holes on the top seals of oviparous channels;the spatial distribution of this insect was tested as an aggregated distribution and the cause of this aggregation had something with biological characteristics and population dependence of its individuals and host distribution;in the years when it is rainy or continuously overcast and rainy,its imago population would increase ;going through a warm winter,the population skimp damnify in hibernalisation,so walnut fruits would be severely damaged ;low rainfall ,weather with good sunshine ,and cold winter with low temperature would limit the geographical distribution of its populations, according to the results, its prevention and management in walnut production should follow the optimal practice.before its encroachment take place and walnut fruits begin to fall off, weeds under walnut trees should be removed ,ground cracks liable to hide fallen fruits be gotten rid of and infested fallen fruits in shade and weedy locations be timely picked and deposed at the fruit-shedding stage.