Location: Subtropical Plant Pathology Research
Title: Chemical Alternatives to Methyl Bromide for Field-Grown Ornamental Crop Production in Florida Authors
Submitted to: International Congress of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: April 20, 2008
Publication Date: December 1, 2008
Citation: Burelle, N.K., Rosskopf, E.N., Mcsorley, R. 2008. Chemical Alternatives to Methyl Bromide for Field-Grown Ornamental Crop Production in Florida. International Congress of Nematology. Technical Abstract: Identification of alternatives to methyl bromide for field-grown ornamental crops in the U.S. is particularly challenging because of the need to control rogues (off-varieties), limited availability of labeled materials, difficulty gluing wide sheets of virtually impermeable films for broadcast fumigation, and the proximity of occupied structures to production areas. Numerous commercial and experimental field trials were conducted under a range of nematode, weed, and pathogen pressures in southeastern and south central Florida to evaluate broadcast applications of Midas™ (iodomethane:chloropicrin 50:50), and Paladin™ (dimthyldisulfide (DMDS): chloropicrin 79:21). Crops included snapdragon (Antirrhinum majus), celosia (Celosia argentea var. cristata), sunflower (Helianthus annuus), delphinium (Delphinium elatum), and caladium (Caladium hortulanum). Overall, both Midas and Paladin provided nematode and weed control comparable to methyl bromide (MeBr) with no significant phytotoxicity observed in any of the crops tested. Immediately following treatment, both compounds reduced Meloidogyne spp. juveniles in soil as well as MeBr, and recolonization often occurred more slowly in Midas treatments compared to MeBr. However, under subtropical conditions and high nematode pressure, parasitic nematodes rebounded to similar levels in all treatments by 10 weeks after fumigation. Interestingly, Midas and Paladin allowed for faster recolonization of soil by microbivorous nematodes than MeBr. In caladium, a long-season crop (10 months), no differences in nematode control were observed among the three fumigants by the end of the season. However, Paladin resulted in lower total yield than MeBr. Application of Midas and Paladin requires more oversight and precision because these compounds are much less volatile than MeBr, and therefore do not move as well through the soil. Future research on chemical alternatives for this industry will focus on three new compounds, citroxin, ethanedinitrile, and 2-bromoethanol, which have demonstrated potential for control of Meloidogyne spp., weeds, and pathogens.