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A Reflection on My Research in Weed Biological Control: Using What We Have Learned for Future Applications

Published online by Cambridge University Press:  20 January 2017

Raghavan Charudattan*
Affiliation:
Plant Pathology Department, University of Florida Institute of Food and Agricultural Sciences, Gainesville, FL 32611
*
Corresponding author's E-mail: [email protected].

Abstract

When I began my foray into the field of biological control of weeds in 1971, the concept of deliberately using pathogens to control weeds was novel and untested and met with skepticism and resistance. Soon, a worldwide network of plant pathologists, weed scientists, microbial technologists, formulation specialists, and regulatory personnel came together to study, develop, and apply pathogens in safe and effective ways of control of a variety of weeds in crops and natural areas. Several new weed–pathogen systems were studied; a few dozen products and pathogens were brought to use, albeit on a very small scale compared to conventional weed-control products; and along the way, some valuable lessons were learned in phytopathology and weed ecology. A seminal body of information was published on the etiology and epidemiology of several diseases of weeds, many new pathogens were discovered and described, and methods were developed for mass production, formulation, and storage of pathogens. Numerous pathogen-produced herbicidal metabolites were discovered and characterized. Protocols were developed, tested, and applied for safe importation and release of exotic pathogens and for registration of microbial herbicides. Spectacular success was achieved with some pathogens used as classical biocontrol agents, and a new class of herbicide, the bioherbicides, came on the scene. Yet some key opportunities were missed. Notably, weed biocontrol research remained largely preoccupied with agent or product development and deployment while great strides were made during this period in phytopathology to understand the genetic–molecular basis of virulence, host range, host specificity, host response to infection, cell death, and pathogen population structure. Nevertheless, the accomplishments in the field of weed biocontrol by pathogens are truly significant. Certainly, we are poised to apply the knowledge gained toward discovery and development of additional weed-control pathogens, but increased effort should be directed also at using pathogen genes, gene products, and genetic mechanisms for weed control. An investment in the latter could help us gain insights into genetically programmed host–pathogen interactions that may be exploited to kill weeds, restrain weed growth, or knock out traits for invasiveness. In our continuing struggle to manage weeds, biocontrol with pathogens should remain a major thrust. Here I present perceptions I have gained from the work that my students, postdoctoral and technical associates, colleagues, and I have done with several weed–pathogen systems.

Cuando empecé mi andar en el campo del control biológico de malezas en 1971, el concepto de uso deliberado de patógenos para controlar malezas era una novedad no probada y me topé con escepticismo y resistencia. Pronto, una red mundial de especialistas patólogos vegetales, científicos de malezas, tecnólogos especialistas en microbiología, especialistas en formulaciones y demás personal regulador se unieron para estudiar, desarrollar y aplicar los patógenos de una manera más segura y efectiva para controlar una variedad de malezas en cultivos y áreas naturales. Muchos de los nuevos sistemas de control de malezas con patógenos fueron estudiados. Algunas docenas de productos patógenos fueron traídos para su uso, aunque en una escala muy pequeña comparada a los productos convencionales en este campo. A lo largo del camino, aprendí algunas lecciones valiosas sobre fitopatología y ecología de malezas. Un creativo cuerpo de información fue publicado sobre etiología y epidemiología de varias enfermedades que atacan a las malezas. Muchos nuevos patógenos fueron descubiertos y clasificados y los métodos se fueron desarrollando para la producción masiva, la formulación y el almacenamiento de patógenos. Numerosos herbicidas metabólicos basados en patógenos fueron descubiertos y clasificados. Los protocolos fueron desarrollados, evaluados y autorizados para la importación y liberación segura de patógenos exóticos y también para su registro como herbicidas microbiales. Se alcanzó un éxito espectacular con algunos patógenos utilizados como agentes clásicos de bio-control, y un nuevo tipo de herbicidas, los bio-herbicidas, salieron al mercado, Aún así, algunas oportunidades claves hacían falta. Notablemente, la investigación sobre el control biológico de malezas permaneció mayormente concentrada en el desarrollo de agentes o productos y con su comercialización, mientras grandes avances se hacían durante este período en fitopatología para entender la base genética molecular de la virulencia, el rango y especificidad de las hospederas, la respuesta de las hospederas a la infección, la muerte celular y la estructura de la población de patógenos. Sin embargo, los logros en el campo del control biológico de malezas utilizando patógenos son verdaderamente significativos. Ciertamente, estamos en el momento oportuno de aplicar los conocimientos obtenidos hacia el descubrimiento y desarrollo de patógenos adicionales. Sin embargo, los esfuerzos también deben ser enfocados al uso de genes de los patógenos, el desarrollo de productos derivados de estos genes y los mecanismos genéticos para el control de malezas. Una inversión en el último concepto podría ayudarnos a ganar terreno en el campo de las investigaciones genéticamente programadas de interacciones de patógenos hospederos que pueden ser explotados para matar malezas, restringir su crecimiento o aniquilar las amenazas de invasión en los cultivos. En nuestra continua lucha para un mejor manejo de malezas, el control biológico con patógenos debe permanecer seguro. En este documento, presento especificaciones que he adquirido del trabajo que mis estudiantes, asociados post-doctorales y técnicos, colegas y yo hemos hecho con varios sistemas de patógenos para el control de las malezas.

Type
Symposium
Copyright
Copyright © Weed Science Society of America 

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