The present and future use of technology to detect plant pathogens to guide disease control in sustainable farming systems

Abstract

As the control of any disease is most effective and economical if addressed at its onset, there is a need to detect potential epidemics before they decrease yields in sustainable farming systems. Diagnostic tests to detect plant pathogens are now based on a number of diverse technologies, yet to be effective a procedure must be simple, accurate, rapid and safe to perform, and be sensitive enough to avoid ‘false positives’. These technologies have developed as considerable skill is required to identify, quantify or even detect the presence of pathogens at the start of an outbreak even when the final symptoms of a disease are frequently conspicuous. Although highly sensitive methods of diagnosis may not be as fast or simple as the conventional visual examination of crop plants for disease symptoms, little training is required to generate routinely reliable results. Since no method of identifying pathogens or diseases is unrivalled in both reliability and simplicity, many diagnostic methods will probably continue to co-exist in some form in the future. In practice, different methods of diagnosing plant disease are often used in a complementary way rather than as alternatives. It is uncertain how much the traditional methods, such as identification by visual inspection of pathogens in situ or in vitro in pure cultures by microscopic examination, will decline as methods based on the molecular biology of pathogens become more prevalent. Electronic communication and retrieval systems are also likely to become useful.