Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 12, 2007
Publication Date: July 1, 2007
Citation: Gerik, J.S. 2007. Floriculture Production with Iodomethane, 1, 3-dichloropropene and Chloropicrin as an Alternatie to Methyl Bromide. American Phytopathological Society Abstracts. Phytopathology 97:s40 Technical Abstract: Cut flower growers in California have routinely used methyl bromide and chloropicrin soil fumigation to control soilborne pathogens and weeds. Because of the ban on methyl bromide production and import, alternative treatments are required. Three field trials were established to test alternative treatments. Fumigants and irrigation water were applied through three irrigation tapes. All three trials contained the same treatments: 1) 448 kg ha-1 methyl bromide + chloropicrin (50:50); 2) 448 kg ha-1 iodomethane + chloropicrin (50:50); 3) 443 kg ha-1 1, 3-dichloropropene + chloropicrin (61:35); and 4) a water control. The fields were tilled and weed free before fumigation. Populations of Pythium spp. and Fusarium oxysporum were determined from soil samples collected after treatment. Trial 1 was seeded with stock, trial 2 was transplanted with seedlings of snapdragon, and trial 3 was planted with bulbs of Dutch iris. Growth parameters and weed counts were made. The chemical treatments reduced the populations of Pythium spp. relative to the control plots. F. oxysporum was reduced only in trial 3. Weed control was variable. Stem rot, caused by, Sclerotinia sclerotiorum, was not reduced by any treatment. In conclusion, the two alternative treatments perform as well as the standard methyl bromide + chloropicrin treatment, but they are not registered for use in flower crops.