Submitted to: European Meeting in the IOBC/WPRS Working Group
Publication Type: Proceedings
Publication Acceptance Date: 10/1/2011
Publication Date: 12/1/2011
Citation: Weller, D.M., Paulitz, T.C., Okubara, P.A., Mavrodi, D.V., Schroeder, K.L., Bonsall, R.F., Mavrodi, O.V., Parejko, J.A., Thomashow, L.S. 2011. Effects of Traditional and New Agricultural Practices on Pathogen and Biological Control Agents Populations and on Soil Suppressiveness. European Meeting in the IOBC/WPRS Working Group. Vol. 71, pp 159-167. Interpretive Summary: By the year 2050, there will be at least nine billion people on earth to feed using the same amount or less land and water as is currently available. One-third of all agricultural commodities grown worldwide are lost to diseases and other pests, and soilborne diseases account for a significant amount of those annual losses. Crop plants often lack resistance to many soilborne fungal pathogens and pathogenic nematodes. Microbial-based mechanisms are often the first line of defense for roots against soilborne diseases. Over the last four decades, considerable progress has been made in understanding and in enhancing microbial-based methods of disease control, which has improved the management of soilborne diseases especially in cereal-based cropping systems. Farmers worldwide are being challenged to use less pesticides and fumigants and to apply more sustainable cropping-practices. In addition, greater numbers of consumers are demanding pesticide-free food. The call for increased sustainability in farming and the need to produce more food will present tremendous challenges to develop inexpensive and highly effective biologically based methods to control diseases and other pests. This paper focuses on describing sustainable cultural and biological approaches to control soilborne diseases.
Technical Abstract: By 2050, there will be 9 billion people on earth to feed using the same amount or less land and water as is currently available for agricultural production. Currently about one third of all agricultural commodities grown worldwide are lost to diseases, insects and other pests. Soilborne diseases account for a significant amount of those annual losses in food production, and crop plants often lack resistance to soilborne pathogens. Farmers will need to increase production, but must do so using less pesticides and more sustainable cropping practices. This paper discusses how changes in agricultural practices that are needed to enhance sustainability in 21st century wheat production also impact populations of soilborne pathogens and diseases, disease suppressive soils and populations of biocontrol agents. We focus on the Pacific Northwest of the USA, and more specifically on wheat production in the state of Washington. Changes to more sustainable agricultural practices such as reduced tillage have led to an increase in the incidence of soilborne diseases but new agricultural practices as well as techniques in precision agriculture and molecular detection of soilborne pathogens are finding solutions to disease problems. Indigenous biocontrol Pseudomonas spp. such as those producing 2,4-diacetylphloroglucinol and phenazine-1-carboxylic acid have a role in natural suppression of disease, but their populations and role in disease suppression are also affected by changes in agricultural practices.