Wilson L J, Lei T T, Sadras V O, Wilson L T, Heimoana S C
CSIRO Division of Plant Industry and Cotton Catchment Communities CRC, Locked Bag 59, New South Wales, Australia.
Bull Entomol Res. 2009 Oct;99(5):467-78. doi: 10.1017/S0007485308006500. Epub 2009 Feb 10.
Understanding the compensatory responses of crops to pest damage is important in developing pest thresholds. Compensation for pest damage in crops can occur at the plant level, where the architecture, growth dynamics and allocation patterns of damaged plants are altered, allowing them to recover or, at the crop level, where differential damage between plants may alter plant-to-plant interactions. We investigated growth and yield of cotton (Gossypium hirsutum L.) following non-uniform manual defoliation of seedlings. This partially replicates real pest damage and is valuable in understanding crop-level responses to damage because it can be inflicted precisely. Damage distributions included damaging 0, 25, 50, 75 or 100% of the plants. Damage intensity for the damaged plants was varied by removing 100 or 75% of each true leaf when plants had two, four and six true leaves. At the crop level, yield loss increased as the proportion of plants damaged and intensity of damage per damaged plant increased. Neighbour interactions occurred; undamaged plants with damaged neighbours grew larger and yielded better than undamaged plants with undamaged neighbours, while the converse applied for damaged plants with undamaged neighbours. Neighbour interactions were influenced by the intensity of damage and were stronger when 100% of the leaf area was removed than when 75% was removed. At the crop level, when compared with yield estimates based on yield of plants from uniformly damaged or undamaged plots, these interactions resulted in higher yield than expected (+8%). This suggests that damage distribution may have to be considered in studies where artificial or real pest damage is inflicted uniformly on plants.
了解作物对害虫损害的补偿反应对于制定害虫阈值至关重要。作物对害虫损害的补偿可在植株水平发生，受损植株的结构、生长动态和分配模式会发生改变，使其得以恢复；也可在作物水平发生，植株间的差异损害可能会改变植株间的相互作用。我们研究了棉花（陆地棉）幼苗非均匀人工去叶后的生长和产量。这部分模拟了实际的害虫损害，对于理解作物水平对损害的反应很有价值，因为可以精确施加损害。损害分布包括损害0%、25%、50%、75%或100%的植株。当植株有两片、四片和六片真叶时，通过摘除每片真叶的100%或75%来改变受损植株的损害强度。在作物水平上，产量损失随着受损植株比例和每株受损植株的损害强度增加而增加。邻株间存在相互作用；有受损邻株的未受损植株比有未受损邻株的未受损植株长得更大、产量更高，而有未受损邻株的受损植株情况则相反。邻株间的相互作用受损害强度影响，摘除100%叶面积时比摘除75%叶面积时更强。在作物水平上，与基于均匀受损或未受损地块植株产量的产量估计相比，这些相互作用导致产量高于预期（+8%）。这表明在对植株进行均匀人工或实际害虫损害的研究中，可能必须考虑损害分布情况。
