Buchanan Amanda L, Hooks Cerruti R R
Department of Entomology, University of Maryland, College Park, MD.
Environ Entomol. 2018 Apr 5;47(2):292-299. doi: 10.1093/ee/nvy004.
Winter cover crop mulches can diversify agricultural habitats and provide a range of benefits for crop production and pest management. Here we report the influence of strip tilled winter cover crop mulches on arthropod abundance in organic vegetable plots. Crookneck squash (Cucurbita pepo L.; Cucurbitales: Cucurbitaceae) was direct seeded into mowed and strip tilled barley (Hordeum vulgare L.; Poales: Poaceae), crimson clover (Trifolium incarnatum L.; Fabales: Fabaceae), a barley + crimson clover mixture, or a no-cover crop control. Arthropods on squash plants were assessed weekly using visual counts. Seed predation was assessed using weed seed arenas. In 2013, mixed species cover crops produced the most ground cover, fewest weeds, and largest squash plants, but herbivore and predator abundance were not correlated with any of those factors. In 2014, mixed species cover crops again produced the most ground cover and fewest weeds, but the largest squash plants were found in no-cover crop control plots, which also had the highest herbivore abundance per plant. Predator and herbivore abundance were positively correlated with squash plant size in 2014. There were no differences in seed predation across treatments. Differences in ground cover biomass and weed presence between the 2 yr may have contributed to differences in squash plant quality and subsequent herbivore abundance between seasons. Results suggest that arthropods on plants responded largely indirectly to cover crops through host plant quality. Results are interpreted in light of overall costs and benefits of cover cropping.
冬季覆盖作物地膜能使农业栖息地多样化，并为作物生产和害虫管理带来一系列益处。在此，我们报告带状翻耕的冬季覆盖作物地膜对有机蔬菜地块节肢动物数量的影响。将弯颈南瓜（西葫芦；葫芦目：葫芦科）直接播种到经过割草和带状翻耕的大麦（大麦；禾本目：禾本科）、绛车轴草（绛车轴草；豆目：豆科）、大麦 + 绛车轴草混合物或无覆盖作物对照地块中。每周通过目视计数评估南瓜植株上的节肢动物。使用杂草种子培养皿评估种子捕食情况。2013年，混合物种覆盖作物产生的地被植物最多，杂草最少，南瓜植株最大，但食草动物和捕食者的数量与这些因素均无关联。2014年，混合物种覆盖作物再次产生了最多的地被植物和最少的杂草，但最大的南瓜植株出现在无覆盖作物对照地块中，该地块每株植物上的食草动物数量也最高。2014年，捕食者和食草动物的数量与南瓜植株大小呈正相关。各处理间种子捕食情况无差异。两年间地被生物量和杂草存在情况的差异可能导致了不同季节南瓜植株质量及随后食草动物数量的差异。结果表明，植株上的节肢动物很大程度上是通过寄主植物质量对覆盖作物产生间接反应。根据覆盖作物的总体成本和效益对结果进行了解释。
