Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/13/2005
Publication Date: 8/1/2005
Citation: Gerik, J.S. 2005. Evaluation of soil fumigants applied by drip irrigation for liatris production.. Plant Disease. pgs. 883-887. Interpretive Summary: Registered and non-registered chemicals were tested 2 consecutive years as alternatives to methyl bromide in the cut flower crop, gay feather. The chemicals were applied through a standard drip irrigation system, the same system that the grower uses to irrigate the crop. The treatments consisted of various formulations and combinations of Midas®, InLine®, Vapam®, Multiguard®, SEP-100®, and dimethyl disulfide. Most of the formulations gave good control of the soilborne plant pathogen Pythium ultimum. Another soilborne pathogen, Fusarium oxysporum was also controlled, but to a lesser extent. The disease stem rot, caused by Sclerotinia sclerotiorum, developed in the crop the first year and was controlled best by the treatments containing Vapam®, and SEP-100® and to a lesser extent by Tri-Clor EC® and Midas®. Weed control was not good either year. Viable alternatives to methyl bromide for cut flower production will require better weed control than was achieved in this study.
Technical Abstract: Cut flower growers are in need of alternatives to methyl bromide for pathogen and weed control. The efficacy of alternative chemicals, applied by drip irrigation, was tested in a cut flower production system. In 2002, seven chemical formulations were tested: chloropicrin, iodomethane + chloropicrin, 1, 3-dichloropropene + chloropicrin, sodium azide, metham sodium, furfural + allyl isothiocyanate, and furfural + metham sodium. In 2003, an additional treatment, dimethyl disulfide was added. Most of the treatments reduced populations of Pythium ultimum and Fusarium oxysporum. Metham sodium, furfural + metham sodium, sodium azide, and chloropicrin significantly reduced the incidence of Liatris stem rot caused by Sclerotinia sclerotiorum. Weed control was not acceptable either year for any of the treatments. Viable alternatives to methyl bromide for cut flower production will require better treatments for weed control than was achieved in this study.