Author
 |
Deloach Jr, Culver |
|
Submitted to: Biological Control Symposium Proceedings
Publication Type: Proceedings Publication Acceptance Date: 12/16/2004 Publication Date: 2/28/2005 Citation: DeLoach, C.J. 2004. Control biologico de malezas. In: Memoria del XV Curso Nacional de Control Biologico, November 8-13, 2004, Los Mochis, Mexico. p. 116-135. Interpretive Summary: One of the greatest threats to agriculture, natural ecosystems and human health in North America is the annual introduction of huge numbers of plants, insects and other animals, and pathogens from other areas of the world. Evolving public perceptions toward private vs. public ownership and responsibility, consumptive usage vs. conservation, pollution vs. environmental health, technological development, and chemical vs. biological control have strongly influenced concepts of pest control during the past century.For exotic, invasive weeds, the introduction of plant-feeding insects or pathogens that control weeds in their native homelands, has been very successful in many countries in providing efficient, safe, environmentally friendly control of these pests. Biological control of weeds began in 1863 and has been used in 75 countries against 133 weed species, by releasing over 365 different natural enemies. In North America, since its beginning in 1945, biological control has been used against 38 weed species; it has provided substantial or complete control of one third of the weeds, and partial control of another third but improved technology and more concentrated research has improved the success rate to about two-thirds since the 1960s. The general research protocol and methodology is well established, including target weed selection, risk analysis, overseas discovery and testing, quarantine testing, release and establishment, and evaluation of control and environmental effects. Methods of safety testing are well developed and always have correctly predicted which plants will be fed on after release of the control agents. However, the methods of predicting degree of control after release are uncertain and improvements that can reduce the number of control agents required are under intense investigation. These improvements will secure the role of biological control as perhaps the most safe and efficient means of reducing populations of weedy pests. Technical Abstract: Biological control of weeds began in 1863 and has been used in 75 countries against 133 weed species, by releasing over 365 different natural enemies. It has provided substantial or complete control of one third of the weeds, and partial control of another third. Only 7 cases of transient damage has occurred to non-target plants and only 1 case of heavy damage resulting in stand reduction. It is most useful against exotic, invasive weeds of natural ecosystems, aquatic systems and rangelands. It is highly specific to the target weed, permanent and low-cost. Historically, only 1 to 3 control agents have provided nearly all of the control, no case of resistance to the control agents is known, no mistake in host specificity prediction has occurred, and no change in host range by the control agent has occurred. The general research protocol and methodology is well established, including target weed selection, risk analysis, overseas discovery and testing, quarantine testing, release and establishment, and evaluation of control and environmental effects. Changing public perceptions of environmental values requires more efficient methods for selecting natural enemies for efficacy and several improvements are under investigation. |
