大麦田草地贪夜蛾的发生为害及抽样技术

草地贪夜蛾在中国可取食为害玉米、高粱、小麦等禾本科作物,但其在大麦田的发生为害情况尚不清楚。我们对云南省曲靖市马龙区处于苗期至分蘖期大麦田的调查结果表明,草地贪夜蛾的虫田率高达62.5%、大麦受害株率为9.33%~100%、虫口密度为1~46头/m2,其中1~3龄幼虫比例达98.6%,受害株率与虫口密度呈显著正相关。大多数草地贪夜蛾幼虫藏匿于大麦心叶为害,取食后叶片形成半透明薄膜窗孔,幼虫在大麦田呈聚集分布。基于空间分布型的研究结果,我们提出了大麦田草地贪夜蛾幼虫理论抽样模型。本研究表明草地贪夜蛾可对大麦生产构成严重威胁。研发的幼虫抽样方法为大麦田草地贪夜蛾幼虫种群调查提供了技术支撑。

Population occurrence and sampling technique of fall armyworm Spodoptera frugiperda in barley field

Fall armyworm, Spodoptera frugiperda (J.E.Smith) could cause severe damage on gramineous crops in China, such as corn, surgeon and wheat, however, its occurrence in barley field is unexplored. In this study, the damage and spatial distribution of S. frugiperda in barley field were investigated in Malong district, Qujing city, Yunnan province. The barley was all at seedling to tillering stages. The results indicated that the percentage of barley fields infected by S. frugiperda was 62.5%, the percentage of damaged plants ranged from 9.33% to 100%, the average larval densities ranged from 1 to 46 individuals per meter square and early larvae at 1st to 3rd instar were found at high percentage (98.6%). There is a significant positive correlation between the percentage of damaged plants and larval density. Larvae of fall armyworm usually hide in the barley seedlings plant and feed on the central whorl leaf, resulting in the windowpane injury. Spatial distribution analysis indicated that the larvae on barley took a pattern of aggregation distribution. Further, a theoretical sampling model based on larval density was proposed. This study indicates that S. frugiperda is a serious threat to Chinese barley production, and results in the spatial distribution and theoretical sampling model provides a technical support for population density survey and control of S. frugiperda in barley field.