Submitted to: Methyl Bromide Alternatives and Emissions Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/2/2002
Publication Date: 11/6/2002
Citation: GERIK, J.S., ELMORE, C.L., GREEN, I.D. ALTERNATIVE SOIL TREATMENTS FOR FIELD GROWN ORNAMENTALS.. METHYL BROMIDE ALTERNATIVES AND EMISSIONS RESEARCH CONFERENCE PROCEEDINGS. 2002. Interpretive Summary: A trial was established in Marina, CA to test alternatives to methyl bromide for calla lily flower and rhizome production. Chemicals were applied through the drip irrigation tape. Chemical treatments included Chloropicrin, metham sodium, sodium azide, iodomethane, 1.3-dichloropropene, and furfural; alone and in various combinations. Preliminary data indicate that the treatments containing chloropicrin are the most efficacious for controlling weeds and disease pathogens in a severely infested calla field. It appears the amount of water used to apply the fumigants may be important in some instances.
Technical Abstract: A trial was established in Marina, CA to test alternatives to methyl bromide for calla lily flower and rhizome production. The major pest targets were weeds and soilborne pathogens. Chemicals were applied through the drip irrigation tape in either 33mm or 67mm of water based on bed width on May 2nd & 3rd 2002. A split-plot design was utilized; the main plots are the amount of water used, and the subplots are the chemicals applied. There are 6 replications. Prior to treatment, sachets containing rhizomes of calla lily, nutsedge, and seed of mustard and malva were buried in each plot at 5 and 15cm depth. Chemical treatments included chloropicrin (448 kg/ha), furfural + metham sodium (50/50 673 kg/ha), sodium azide (112 kg/ha), iodomethane + chlorpicrin (50/50 336 hg/ha & 33/67 448 kg/ha), 1.3-dichloropropene (272 kg/ha) and, 1.3-dichloropropene + chlorpicrin (65/35 628 kg/ha). A water control was added. Control of malva buried in the sachets was not significantly different for any treatment from the control. Most of the treatments significantly controlled the nutsedge, mustard and the calla rhizomes buried in the sachets except sodium azide. The high water rate improved control of weeds in some instances. All of the chemical treatments significantly controlled existing weeds, malva, nutsedge, and clover. Populations of Pythium sp. that were over 500 propagules per gram of soil in the control plots were significantly reduced by all treatments to less than 100. Populations of Phytophthora were similarly reduced by all treatments from over 20 to less than 3 for all treatments except for sodium azide. All treatments except for sodium azide significantly improved stand count 45 days after sowing. These preliminary data indicate that the treatments containing chloropicrin are the most efficacious for controlling weeds and disease pathogens in a severely infested calla field. It appears the amount of water used to apply the fumigants may be important in some instances. These are only preliminary data. More data are being developed on populations of other pathogens. Next summer disease data will be collected along with more weed control data. This trial will continue for over a year. At the conclusion of the trial, data will collect yield data from the harvest of the rhizomes.