Timper Patricia
Crop Protection and Management Research Unit, USDA ARS, P. O. Box 748, Tifton, GA 31793.
J Nematol. 2014 Jun;46(2):75-89.
Conservation biological control is the modification of the environment or existing practices to protect and enhance antagonistic organisms to reduce damage from pests. This approach to biological control has received insufficient attention compared with inundative applications of microbial antagonists to control nematodes. This review provides examples of how production practices can enhance or diminish biological control of plant-parasitic nematodes and other soilborne pests. Antagonists of nematodes can be enhanced by providing supplementary food sources such as occurs when organic amendments are applied to soil. However, some organic amendments (e.g., manures and plants containing allelopathic compounds) can also be detrimental to nematode antagonists. Plant species and genotype can strongly influence the outcome of biological control. For instance, the susceptibility of the plant to the nematode can determine the effectiveness of control; good hosts will require greater levels of suppression than poor hosts. Plant genotype can also influence the degree of rhizosphere colonization and antibiotic production by antagonists, as well the expression of induced resistance by plants. Production practices such as crop rotation, fallow periods, tillage, and pesticide applications can directly disrupt populations of antagonistic organisms. These practices can also indirectly affect antagonists by reducing their primary nematode host. One of the challenges of conservation biological control is that practices intended to protect or enhance suppression of nematodes may not be effective in all field sites because they are dependent on indigenous antagonists. Ultimately, indicators will need to be identified, such as the presence of particular antagonists, which can guide decisions on where it is practical to use conservation biological control. Antagonists can also be applied to field sites in conjunction with conservation practices to improve the consistency, efficacy, and duration of biological control. In future research, greater use should be made of bioassays that measure nematode suppression because changes in abundance of particular antagonists may not affect biological control of plant parasites.
保育生物防治是指通过改变环境或现有措施来保护和增强拮抗生物，以减少害虫造成的损害。与大量应用微生物拮抗剂来防治线虫相比，这种生物防治方法受到的关注不足。本综述提供了一些实例，说明生产实践如何增强或削弱对植物寄生线虫和其他土传害虫的生物防治效果。通过提供补充食物来源，如向土壤中施用有机改良剂时的情况，可以增强线虫的拮抗生物。然而，一些有机改良剂（如含有化感化合物的粪肥和植物）也可能对线虫拮抗生物有害。植物物种和基因型可强烈影响生物防治的结果。例如，植物对线虫的易感性可决定防治效果；优质寄主比劣质寄主需要更高水平的抑制。植物基因型还可影响拮抗生物在根际的定殖程度和抗生素产量，以及植物诱导抗性的表达。轮作、休耕期、耕作和施用农药等生产实践可直接破坏拮抗生物的种群。这些实践还可通过减少其主要线虫寄主而间接影响拮抗生物。保育生物防治面临的挑战之一是，旨在保护或增强对线虫抑制作用的措施在所有田间地点可能都无效，因为它们依赖于本地拮抗生物。最终，需要确定一些指标，如特定拮抗生物的存在情况，以指导关于在何处实际可行使用保育生物防治的决策。拮抗生物也可与保育措施一起应用于田间地点，以提高生物防治的一致性、效果和持续时间。在未来的研究中，应更多地使用测量线虫抑制作用的生物测定法，因为特定拮抗生物数量的变化可能不会影响对植物寄生虫的生物防治。
