However, fewer isolates can suppress plant diseases under diverse growing conditions and fewer still have broad-spectrum activity against multiple pathogenic taxa.

When testing bacterial and fungal isolates from the environment for biocontrol activities, between 1 and 10% show at least some capacity to inhibit the growth of pathogens in vitro. Interactions that lead to biocontrol can include antibiosis, competition, induction of host resistance, and predation (7). The interactions between microorganisms and plant hosts can be complex. Over the past one hundred years, research has repeatedly demonstrated that phylogenetically diverse microorganisms can act as natural antagonists of various plant pathogens (6) (Fig. Treatments differing in their efficacy are shown, from left to right: untreated (Un), CaCl 2, chlorothalonil (Fung), and the biocontrol agent Trichoderma hamatum T382 inoculated into the potting mix (T382). Begonias were grown in the greenhouse and inoculated with Botrytis cinerea under conditions optimal for the development of disease. Example bioassay for biological control of a plant pathogen.

We conclude by describing future prospects for using biological control to limit the damage of plant pathogens in both conventional and organic agriculture. Here, we use the term biological control in the broader sense as we describe the current status of research, commercial development, and application of biocontrol strategies targeted at plant pathogens. Furthermore, natural products and chemical compounds discovered as a result of basic research into the molecular mechanisms of pathogenesis and biological control have led to the development of вЂњbiorationalвЂќ pesticides. However, the interrelationships of many environmental variables can result in multiple interactions among organisms and their environment, several of which might contribute to effective biological control. In the narrowest sense, biocontrol involves suppressing pest organisms with other organisms. Plant pathogens are just one class of targets of biological control, which also is designed to limit other pests such as insects, parasitic nematodes, and weeds. Plant Health Progress doi:10.1094/PHP-2002-0510-01-RV.Д«iological control of plant pests and pathogens continues to inspire research and development in many fields. Biological control of plant pathogens: Research, commercialization, and application in the USA. Fravel, Vegetable Laboratory, USDA, ARS, Beltsville, MD 20705Д¬orresponding author: Brian B. McSpadden Gardener, Department of Plant Pathology, The Ohio State University-OARDC, Wooster, OH 44691 and Deborah R.

Increase in gall fly biocontrol agents