?虽然大家普遍认为植物病菌是有害的，但美国植物病理协会（APS）的植物病理学家认为，植物病菌可能是一种有效的控制杂草生长的工具。
??利用植物病菌来抑制杂草生产被认为是控制其生产的一种方法，但这种方法是不适合于使用化学除草剂的区域。美国农业部Fort Pierce, FL.，Erin Rosskopf说：“为了阻止杂草的生长或减少除草剂对环境的影响，除草剂的选择或使用必须和其他方法相配合，植物病菌也可能被使用来控制杂草的生长。”
??由于大量的杂草影响农业的产量，所以说杂草的控制是很重要的。杂草使农业产量下降了12%（引起的损失达320亿美元以上），美国每年大约有2670亿美元的农业收入。杂草也带来了严重的生态学问题。侵袭性的杂草可能会改变生态系统的程序，从而取代天然的植物和动物物种。另外，杂草也是影响农作物的植物病菌的宿主。
??根据Rosskopf研究，有两种方法控制杂草生长，一种是植物病菌---经典的生物防治途径，另一种是生物除草剂途径。经典的生物防治途径是运用少量的科技处理，借助异质病菌来控制驯化杂草。
??“正如引入昆虫一样，使用引入病菌的经典生物防治途径没有任何的意外和不好的影响，有57%的全面成功。” Florida, Gainesville, FL大学 Raghavan Charudattan说。
??生物除草剂途径是利用从杂草中分离的天然植物病菌和在感染性的繁殖体（例如孢子）上生长的天然植物病菌的一种方法。被应用的感染性的繁殖体会带来高水平的感染，在经济效应丧失之前，这将大大地减少或破坏目的杂草的生长。在生长季节期间，病菌不能普遍幸存，就需要应用一年生植物。据估计，具有潜在的生物除草剂的植物病菌有200种之多。
英文原文：
Fight Weeds With Plant Pathogens
Although plant pathogens are typically viewed as detrimental, plant pathologists with the American Phytopathological Society (APS) say plant pathogens may be a successful, eco-friendly tool for managing weeds.
"The use of plant pathogens to suppress weeds is considered as one of the alternative weed control options for areas or production systems where the use of chemical herbicides is not permitted or feasible," said Erin Rosskopf, USDA, Agricultural Research Service, Fort Pierce, FL. "Plant pathogens may also be used when the herbicide selection or usage must be rotated with other control methods in order to prevent the development of resistant weeds or lessen the impact of herbicides on the environment," she said.
Weed management is important due to the amount of damage weeds can cause to agricultural productivity. Weeds can reduce crop yields by as much as 12 percent (causing up to $32 billion in losses), based on the potential value of all U.S. crops of approximately $267 billion/year. Weeds also pose serious ecological problems. Invasive weeds are capable of altering ecosystem processes and displacing native plant and animal species. In addition, weeds serve as reservoirs for plant pathogens that impact crops.
According to Rosskopf, there are two approaches used for managing weeds with plant pathogens-the classical biological control approach and the bioherbicides approach. The classical biocontrol approach uses a pathogen imported from a foreign location to control a native or naturalized weed with minimal technological manipulations.
"Classical biological control using imported pathogens has an overall success rate of 57 percent and has been just as successful as the use of imported insects, with no instances of unexpected or undesirable effects," says Raghavan Charudattan, University of Florida, Gainesville, FL.
The bioherbicide approach utilizes native plant pathogens that are isolated from weeds and are grown to produce large numbers of infective propagules (such as spores). Infective propagules are applied at rates that will cause high levels of infection, which will greatly reduce the growth of, or kill the target weed before economic losses are incurred. Annual applications are required since the pathogen does not generally survive between growing seasons. It is estimated that there are more than 200 plant pathogens that have been or are under evaluation for their potential as bioherbicides.
More information is available in the first of a two-part series on using plant pathogens for weed biocontrol, located at www.apsnet.org/online/feature/weed1/. APS is a non-profit, professional scientific organization. The research of the organization's 5,000 worldwide members advances the understanding of the science of plant pathology and its application to plant health.
