VATIS UPDATE Article

A team of researchers from University of California Davis, Reiter Affiliated Companies, Ramco Norcal and Driscoll’s Strawberry Assoc. Inc., the United States, have reported weed and pathogen control results with steam as well as fruit yields over four strawberry production seasons (2011/12, 2012/13, 2013/14 and 2014/15). Steam was applied by a proto-type tractor towed steam machine with a Clayton steam generator. Steam controls weeds and soil borne pests and strawberry yields usually increase with steam up to 20% compared to common non-chemical pre plant soil disinfestation treatments in California.

The results suggest that these steam induced benefits are due to combined effects of extra nutrient release and reduction of pathogen pressure. The team is currently separating those effects in controlled experiments. Furthermore researchers investigate steam induced changes in soil microbial community and the utilization of steam in combination with allyl isothiocyanate (AITC) and cover crops as management tool. A commercial flat field steam applicator is being manufactured in cooperation with industry.

Previous and current investigations have shown that steam has to be considered as alternative soil disinfestation method for California strawberry production. Depending on field conditions, steam shows similar or better pest and weed control efficacy than common chemical and non-chemical soil disinfestation methods. However, it is critical that constant soil temperatures are achieved throughout the treatment.