Most broadly, biological control is the suppression of damaging activities of one organism by one or more other organisms, often referred to as natural enemies. Published definitions of biocontrol differ depending on the target of suppression number, type and source of biological agents and the degree and timing of human intervention. Because the term biological control can refer to a spectrum of ideas, it is important to stipulate the breadth of the term when it is applied to the review of any particular work. National Research Council took into account modern biotechnological developments and referred to biological control as “the use of natural or modified organisms, genes, or gene products, to reduce the effects of undesirable organisms and to favor desirable organisms such as crops, beneficial insects, and microorganisms”, but this definition spurred much subsequent debate and it was frequently considered too broad by many scientists who worked in the field (US Congress, 1995). The various definitions offered in the scientific literature have sometimes caused confusion and controversy.
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And, while such inputs may mimic the activities of living organisms, non-living inputs should more properly be referred to as biopesticides or biofertilizers, depending on the primary benefit provided to the host plant. These formulations may be very simple mixtures of natural ingredients with specific activities or complex mixtures with multiple effects on the host as well as the target pest or pathogen. More broadly, the term biological control also has been applied to the use of the natural products extracted or fermented from various sources. In both fields, the organism that suppresses the pest or pathogen is referred to as the biological control agent (BCA). In plant pathology, the term applies to the use of microbial antagonists to suppress diseases as well as the use of host-specific pathogens to control weed populations. In entomology, it has been used to describe the use of live predatory insects, entomopathogenic nematodes, or microbial pathogens to suppress populations of different pest insects. The terms “biological control” and its abbreviated synonym “biocontrol” have been used in different fields of biology, most notably entomology and plant pathology. This survey will i) describe the various definitions and key mechanisms of biocontrol, ii) explore the relationships between microbial diversity and biological control, iii) describe the current status of research and application of biological controls, and iv) briefly outline future directions that might lead to the development of more diverse and effective biological controls for plant diseases.
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To that end, this article is presented as an advanced survey of the nature and practice of biological control as it is applied to the suppression of plant diseases. Among these alternatives are those referred to as biological controls.Ī variety of biological controls are available for use, but further development and effective adoption will require a greater understanding of the complex interactions among plants, people, and the environment. Consequently, some pest management researchers have focused their efforts on developing alternative inputs to synthetic chemicals for controlling pests and diseases. Additionally, the spread of plant diseases in natural ecosystems may preclude successful application of chemicals, because of the scale to which such applications might have to be applied. Today, there are strict regulations on chemical pesticide use, and there is political pressure to remove the most hazardous chemicals from the market.
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However, the environmental pollution caused by excessive use and misuse of agrochemicals, as well as fear-mongering by some opponents of pesticides, has led to considerable changes in people’s attitudes towards the use of pesticides in agriculture. Such inputs to agriculture have contributed significantly to the spectacular improvements in crop productivity and quality over the past 100 years. Beyond good agronomic and horticultural practices, growers often rely heavily on chemical fertilizers and pesticides. Different approaches may be used to prevent, mitigate or control plant diseases. Plant diseases need to be controlled to maintain the quality and abundance of food, feed, and fiber produced by growers around the world. 5, Juangadh-362 001, Gujarat, Indiaĭepartment of Plant Pathology, Ohio State University, OARDC, Wooster, OH *Permanent address: National Research Centre for Groundnut, Ivnagar Road, PB No. Visiting Scholar, Department of Plant Pathology, Ohio State University, OARDC, Wooster, OH Biological Control of Plant Pathogens The Plant Health Instructor.