Biological control and holistic plant-health care in agriculture

Biological control is defined broadly as the “use of natural or modified organisms, genes, or gene products” to reduce the effects of pests and diseases. Physical control is the use of tillage, open-field burning, heat-treatment (pasteurization), and other physical methods, usually to eliminate pests or separate them from the crop. Chemical control is the use of synthetic chemical pesticides to eliminate pests or reduce their effects. The many approaches to biological control can be categorized conceptionally into 1) regulation of the pest population (the classical approach), 2) exclusionary systems of protection (a living barrier of microorganisms on the plant or animal that deters infection or pest attack), and 3) systems of self-defense (resistance and immunization). The agents of biological control include the pest- or disease-agent itself (sterile males or avirulent strains of pathogens), antagonists or natural enemies, or the plant or animal managed or manipulated (immunized) to defend itself. The methods range from 1) conserving and making maximum use of indigenous (resident) biological control through cultural practices, 2) making one-time or occasional introductions of genes or natural enemies that are more or less self-sustaining and 3) making repeated introductions of a biocontrol agent (e.g. a microbial pesticide). Biological, physical, and chemical treatments and pest controls can be integrated into holistic plant-health care also known as integrated crop and pest management. Eight principles of plant health care are offered: 1) know the production limits of the agroecosystem; 2) rotate the crops; 3) maintain soil organic matter; 4) use clean planting material; 5) plant well-adapted, pest-resistant cultivars; 6) minimize environmental and nutritional stresses; 7) maximize the effects of beneficial organisms; and 8) protect with pesticides as necessary.