By David O. TeBeestDepartment of Plant PathologyUniversity of ArkansasEvery one knows that you take an aspirin to alleviate a headache. Many people even take aspirin to help reduce to heart disease. Plant pathologists have been investigating the role of salicylic acid in a process called systemic acquired resistance (SAR). This compound was first discovered in willow plants (genus Salix) from which the name is derived.
In 1991, the application of acetylsalicylic acid (aspirin) to tobacco leaves induced resistance against Tobacco mosaic virus. In a recent paper in the journal Biological Control, researchers in Alabama reported that SAR against blue mold (a downy mildew disease caused by an Oomycete) in tobacco may involve an accumulation of salicyclic acid (SA). More precisely, they found that certain bacteria increased the levels of salicylic acid in the fluid between cells after treatment. The bacteria studied are natural protective bacteria found on the surface of plant roots. This research may lead to ways to induce the natural defense processes in plants as part of the overall disease management program. For more information go to http://www.sciencedirect.com/ to review the paper by S. Zhang, et al, Biological Control 25:288-296.
Views: Root rots are a common problem in the vegetable garden. Various species Pythium (a fungallike organism in the Oomycetes or water molds) cause the rotting of the roots of many plants. Symptoms typically include brown to black lesions and the lack of any small roots attached to the main feeder roots. The above ground symptoms of root rots often appear to be general wilting and collapse of the plant.Click image for an enlarged view and more information.