tailieunhanh - PESTICIDES IN AGRICULTURE AND THE ENVIRONMENT - CHAPTER 2

ĐỊNH NGHĨA CỦA KIỂM SOÁT SINH HỌC Rất khó để xác định kiểm soát sinh học một cách phổ biến là chấp nhận được cho các học viên đa dạng của lĩnh vực này. Tuy nhiên, một định nghĩa rõ ràng là cần thiết để giải thích và phân định ranh giới giữa các quá trình và phương pháp kiểm soát sinh học khác nhau. Định nghĩa đã phát triển trong những năm qua bao gồm các loại khác nhau của kiểm soát sinh học dựa trên hiện nay được coi là dưới sự bảo trợ của kiểm soát sinh học | 2 Biological Control Raghavan Charudattan and S. Chandramohan University of Florida Gainesville Florida . Gabriela S. Wyss Research Institute of Organic Agriculture Frick Switzerland 1 DEFINITION OF BIOLOGICAL CONTROL It is difficult to define biological control in a manner that is universally acceptable to the diverse practitioners of this field. However a clear definition is necessary to explain and delimit different biological control processes and methodologies. Definitions have evolved over the years to encompass different types of biologically based controls that are now considered under the umbrella of biological control. In this chapter we follow the definition proposed by Charudattan et al. 1 Biological control is the reduction or mitigation of pests and pest effects through the use of natural enemies. Biotechnologies dealing with the elucidation and use of natural enemy s genes and gene products for the enhancement of biological control agents are considered a relevant part of modern biological control. There are several reasons for seeking biological control for pest and disease management. It is well known that chemical pesticides and chemically based controls have limitations notwithstanding the fact that chemical pesticides and the chemical pesticide industry have been responsible to a great extent for enabling food production for the world s burgeoning population. Nonetheless it must be remembered that chemical pesticides are in essence compounds that disrupt the normal metabolic functions of target organisms. They have side effects or nontarget effects that may lead to a series of changes that adversely affect organisms that constitute the ecological web. Some or all of these adverse changes may be passed along the food chain ultimately affecting human and environmental health. 2 BENEFITS AND LIMITATIONS OF BIOLOGICAL CONTROL Biological control has strengths as well as weaknesses. On the beneficial side biocontrol agents are typically .