Skirvin D J, Kravar-Garde L, Reynolds K, Wright C, Mead A
University of Warwick, Wellesbourne, UK.
Bull Entomol Res. 2011 Dec;101(6):623-31. doi: 10.1017/S0007485310000659. Epub 2011 Jan 20.
Within-crop habitat manipulations have the potential to increase the biological control of pests in horticultural field crops. Wildflower strips have been shown to increase the abundance of natural enemies, but there is little evidence to date of an impact on pest populations. The aim of this study was to determine whether within-crop wildflower strips can increase the natural regulation of pests in horticultural field crops. Aphid numbers in plots of lettuce grown adjacent to wildflower strips were compared with those in plots grown in the absence of wildflowers. The presence of wildflower strips led to a decrease in aphid numbers on adjacent lettuce plants during June and July, but had less impact in August and September. The decrease in aphid numbers was greatest close to the wildflower strips and, the decrease in aphid numbers declined with increasing distance from the wildflower strips, with little effect at a distance of ten metres. The main natural enemies found in the crop were those that dispersed aerially, which is consistent with data from previous studies on cereal crops. Analysis and interpretation of natural enemy numbers was difficult due to low recovery of natural enemies, and the numbers appeared to follow changes in aphid abundance rather than being directly linked to the presence of wildflower strips. Cutting the wildflower strips, to remove floral resources, had no impact on the reduction in aphid numbers achieved during June and July, but decreased the effect of the wildflower strips during August and September. The results suggest that wildflower strips can lead to increased natural regulation of pest aphids in outdoor lettuce crops, but more research is required to determine how this is mediated by natural enemies and how the impact of wildflower strips on natural pest regulation changes during the growing season.
作物内部栖息地的调控措施有潜力增强园艺大田作物中害虫的生物防治效果。研究表明，野花带可增加天敌数量，但迄今为止，几乎没有证据表明其对害虫种群有影响。本研究的目的是确定作物内部的野花带是否能增强园艺大田作物中害虫的自然调控能力。将与野花带相邻种植的生菜地块中的蚜虫数量与没有野花的地块中的蚜虫数量进行了比较。野花带的存在导致6月和7月相邻生菜植株上的蚜虫数量减少，但在8月和9月的影响较小。蚜虫数量的减少在靠近野花带的地方最为明显，并且随着与野花带距离的增加，蚜虫数量的减少幅度下降，在距离野花带十米处几乎没有影响。在作物中发现的主要天敌是通过空中扩散的天敌，这与先前对谷类作物的研究数据一致。由于天敌回收率低，对天敌数量的分析和解释很困难，而且天敌数量似乎跟随蚜虫数量的变化，而不是与野花带的存在直接相关。切断野花带以去除花卉资源，对6月和7月实现的蚜虫数量减少没有影响，但在8月和9月降低了野花带的效果。结果表明，野花带可导致户外生菜作物中害虫蚜虫的自然调控增加，但需要更多研究来确定这是如何由天敌介导的，以及野花带对自然害虫调控的影响在生长季节如何变化。
