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United States Department of Agriculture

Agricultural Research Service

Research Project: Alternatives to methyl bromide soil fumigation for vegetable and floriculture production

Location: Subtropical Plant Pathology Research


item Rosskopf, Erin
item Burelle, Nancy
item Butler, David
item Fennimore, Steve

Submitted to: Proceedings of Methyl Bromide Alternatives Conference
Publication Type: Proceedings
Publication Acceptance Date: 10/11/2010
Publication Date: 10/15/2010
Citation: Rosskopf, E.N., Burelle, N.K., Butler, D.M., Fennimore, S. 2010. EVALUATION OF STEAM FOR NEMATODE AND WEED CONTROL IN CUT FLOWER PRODUCTION IN FLORIDA. Proceedings of Methyl Bromide Alternatives Conference. 83:1-3.

Interpretive Summary:

Technical Abstract: A field trial was established on a commercial flower production farm in Palm City, FL. Treatments included MB check under Canslit® metalized film, solarization alone, steam treatment after solarization using 3 inch perforated tile, and steam treatment following solarization using custom-drilled drain tile with 1/16 in. holes spaced every 1.5 in. Drain tile was buried at 14 in. depth from the soil surface in order to adequately heat soil for optimal nematode control in a long-term flower crop. Prior to treatment application and plastic installation, soil samples were collected from each plot and analyzed for baseline nematode numbers. Nematodes from the subsample were identified as either root-knot nematodes or free-living nematodes using an inverted microscope. Steam application followed the four week solarization period in mid-October. All steam was generated using the Sioux propane boiler system. Plots were steamed for sufficient time to reach the target temperature of 70°C for 20 min. Solarization plastic was retained on the plots during steaming and these were also covered with a layer of carpet padding to provide additional insulation. Steam and solarization treatments resulted in root-knot nematode numbers in soil that were lower than MB in snapdragon plots. Root-knot nematode juveniles in snapdragon roots were highest in the solarization treatment. Galling of snapdragon roots was significantly lower in both steam treatments compared with MB and solarization At the end of the season root-knot nematodes in larkspur roots in the steam 2 treatment were reduced to the same level as with MB. Galling on larkspur was lower in both steam treatments than in the MB treatment. Steam treatments killed all nutsedge that had emerged under the plastic, but differences between treatments were not statistically significant due to high variability in nutsedge distribution. Soon after treatment application, solarization plots had significantly more goosegrass and spurge remaining alive than either steam or methyl bromide treatments. In the snapdragon crop, Carolina geranium was a dominant weed and was most effectively controlled by the MB treatment and steam method 2. White clover was most effectively controlled by steam method 2, the total of which was significantly lower than in solarization plots. Total weight of weeds collected from the delphinium subplots was lower in the MB and steam plots than in those treated with solarization alone. There were no differences between the numbers of marketable stems taken from larkspur plots with the order of treatments being methyl bromide, steam method 2, solarization, and steam method 1. Snapdragons, the most nematode susceptible crop, had yields that were statistically similar, but in the order of steam 1, steam 2, MB, and solarization.

Last Modified: 08/20/2017
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