Prospects for composts and biocontrol agents as substitutes for methyl bromide in biological control of plant diseases

摘要

Methyl bromide, an effective soil fumigant for control of soilborne plant pathogens, is scheduled to be phased out by 2005 because of its negative impacts on the environment. Many chemical alternatives to methyl bromide have been proposed but so far, none have proved as effective. Composts have long been recognized to provide a degree of control of diseases caused by soilborne plant pathogens. For this reason, disease-suppressive effects of composts have been investigated intensively over the pasttwo decades. Many compost quality factors must be controlled to obtain consistent effects with these organic amendments. The composition of the organic matter from which the compost is prepared, the composting process itself, the stability or maturity ofthe compost, the quantity of available plant nutrients provided by the compost, loading rates, time of application, and other factors all must be controlled. These and other factors are reviewed. Despite these difficulties, the use of compost for disease control is increasing rapidly. The nursery industry for decades has taken advantage of this benefit associated with compost utilization.