Reardon B J, Spurgeon D W
Areawide Pest Management Research Unit, USDA-ARS, 2771 F&B Road, College Station, TX 77845, USA.
J Econ Entomol. 2003 Apr;96(2):328-33. doi: 10.1603/0022-0493-96.2.328.
It is commonly believed that colonization of early-season cotton, Gossypium hirsutum L., by overwintered boll weevils, Anthonomus grandis grandis Boheman, is concentrated on field margins. However, supporting experimental evidence is not available. In 1999 and 2000, we examined colonization patterns of overwintered boll weevils in Central Texas cotton on the bases of adult collections by a pneumatic sampler and hand collections of abscised infested squares. Samples were taken from sites arranged in a grid that extended inward >70 m from the field margin. Adults were collected from shortly after seedling emergence until the flowering stage, and infested squares were collected during the one-third grown square stage. Despite numerical trends, the numbers of adult weevils collected were not significantly different between years or sexes, or among plant phenological stages. Field-to-field variation among collections was considerable and likely prevented detection of differences among these factors. Spatial patterns represented by adult weevil and infested square collections were examined by logistic regressions fitted to the respective probabilities of weevil detection at each designated sample site. Although we observed trends for slightly decreased probability of weevil detection with increased distance from the field margin, these trends were too weak to be demonstrated statistically. Our results indicate the boll weevil does not consistently exhibit a strong edge-oriented colonization pattern, and that management tactics that are predicated on these patterns, such as border sprays, should be used with caution.
人们普遍认为，越冬棉铃象甲（Anthonomus grandis grandis Boheman）对早熟棉花（Gossypium hirsutum L.）的定殖集中在田边。然而，目前尚无支持这一观点的实验证据。在1999年和2000年，我们基于用气动采样器收集成虫以及人工收集脱落的受害棉蕾，研究了得克萨斯州中部棉花田中越冬棉铃象甲的定殖模式。样本取自一个网格状分布的地点，该网格从田边向内延伸超过70米。从幼苗出土后不久到开花期收集成虫，在棉蕾生长到三分之一大小时收集受害棉蕾。尽管有数值上的趋势，但收集到的成虫数量在年份、性别或植物物候阶段之间并无显著差异。不同田块间收集数据的差异相当大，这可能妨碍了对这些因素差异的检测。通过对每个指定采样点象甲检测概率进行逻辑回归分析，研究了成虫和受害棉蕾收集数据所代表的空间模式。尽管我们观察到随着与田边距离的增加，象甲被检测到的概率有略微下降的趋势，但这些趋势微弱，无法进行统计学证明。我们的结果表明，棉铃象甲并非始终呈现出强烈的边缘定殖模式，基于这些模式的管理策略，如田边喷雾，应谨慎使用。
