Current status of chemical alternative technologies for managing soil borne diseases

Field research continues to focus on a co-application approach of different fumigants, herbicides, and other alternative tactics to achieve pest control efficacy and crop growth response similar to that of methyl bromide. Different application rates, technologies and grower practices are under evaluation in anticipation of potential risk mitigation tactics to reduce buffer zone distances and personal protective equipment requirements being proposed by EPA fumigant reassessments. Both chisel and drip applied fumigant application technologies are being evaluated in conjunction with high barrier, virtually impermeable mulch films to reduce air emissions and fumigant use rates. Drip fumigation procedures under evaluation continue to focus on factors affecting both water and gas phase movement of the different fumigants in soil, including chemical injection period, fumigant concentration, and numbers of drip tubes per bed. Problems with fumigant application and unsuitable environmental conditions appear to be responsible for significant yield and pest control inconsistencies with alternative fumigants. Treatment costs and returns to investment will likely be important economic considerations determining grower use decisions and transition strategy to the alternative fumigants.