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United States Department of Agriculture

Agricultural Research Service

Title: Alternative Chemical Treatments for Ornamental Crops.

Author
item Gerik, James

Submitted to: Proceedings of International Research Conference on Methyl Bromide Alternatives
Publication Type: Proceedings
Publication Acceptance Date: September 1, 2003
Publication Date: November 3, 2003
Citation: GERIK, J.S. ALTERNATIVE CHEMICAL TREATMENTS FOR ORNAMENTAL CROPS.. PROCEEDINGS OF INTERNATIONAL RESEARCH CONFERENCE ON METHYL BROMIDE ALTERNAT. 2003.

Interpretive Summary: Three field trials were established in Oxnard and Carpinteria, CA. to test alternative chemical treatments in ornamental production systems. Treatments at all sites were identical and included the following: iodomethane (30%) + chloropicrin (70%) (Midas, 448 kg/ha Arvesta, San Francisco, CA); Chloropicrin (Tri-Clor EC, 336 kg/ha, TriCal Inc. Hollister, CA); 1,3-dichloropropene (65%) + chloropicrin (35%) (InLine, 577 kg/ha, Dow AgroSciences, Indianapolis, IN); Sodium azide (SEP-100, 112 kg/ha. American Pacific Inc. Las Vegas, NV); Metham sodium (Vapam HL, 477 kg/ha, AMVAC Chemical Inc. Los Angeles, CA); furfural (75%) + allyl isothiocynate (25%) (Multiguard FFA, 672 kg/ha, Harborchem, Cranford, New Jersey); furfural (50%) + metham sodium (50%) (Multiguard Protect, 672 kg/ha, Harborchem, Cranford, New Jersey). All chemicals were applied through the drip irrigation system. At the Oxnard site (Pyramid Flower), treatments were delivered in 2.5 cm of water and at the 2 Carpinteria sites (Hilltop Flowers and Brand Flowers); treatments were delivered in 5 cm of water. Fumigation of the Pyramid Flower site was completed on 14 August 2002, the Hilltop Flower site was completed on 19 November 2002, and the Brand flower site was completed on 4 December 2002. Soil samples were collected from each plot at all 3 sites approximately 3 weeks following the final fumigant application. These soil samples were used to determine population levels of Pythium sp., Phytophthora sp., and Fusarium sp. The Pyramid Flower site was planted with seedlings of Antirrhinum majus (snapdragon) 10 days after the final fumigant application. The Hilltop site was planted with seedlings of Liatris spicata cv callilepsis (gay-feather) on 30 December 2002. Problems arose with the Brand flower site and the only data collected were from the soil samples. Weed counts were made at the Pyramid and Hilltop sites and weeding times were measured for the Hilltop site. Stem rot, caused by Sclerotinia sclerotiorum occurred at the Hilltop site and disease counts were made. The results are presented in the figures that follow. The bars in the figures represent lease significant differences. No Phytophthora sp. were detected at Hilltop or Brand. Most treatments were significantly better than the control for the different parameters measured, but none of the treatments controlled malva, clover or groundsel. Phytophthora sp. and Pythium sp. were controlled better than Fusarium sp. Inline and Midas generally did a good job reducing pathogen populations, but did not reduce the severity of stem rot. More trials are being conducted to further test the efficacy of these fumigants.

Technical Abstract: Three field trials were established in Oxnard and Carpinteria, CA. to test alternative chemical treatments in ornamental production systems. Treatments at all sites were identical and included the following: iodomethane (30%) + chloropicrin (70%) (Midas, 448 kg/ha Arvesta, San Francisco, CA); Chloropicrin (Tri-Clor EC, 336 kg/ha, TriCal Inc. Hollister, CA); 1,3-dichloropropene (65%) + chloropicrin (35%) (InLine, 577 kg/ha, Dow AgroSciences, Indianapolis, IN); Sodium azide (SEP-100, 112 kg/ha. American Pacific Inc. Las Vegas, NV); Metham sodium (Vapam HL, 477 kg/ha, AMVAC Chemical Inc. Los Angeles, CA); furfural (75%) + allyl isothiocynate (25%) (Multiguard FFA, 672 kg/ha, Harborchem, Cranford, New Jersey); furfural (50%) + metham sodium (50%) (Multiguard Protect, 672 kg/ha, Harborchem, Cranford, New Jersey). All chemicals were applied through the drip irrigation system. At the Oxnard site (Pyramid Flower), treatments were delivered in 2.5 cm of water and at the 2 Carpinteria sites (Hilltop Flowers and Brand Flowers); treatments were delivered in 5 cm of water. Fumigation of the Pyramid Flower site was completed on 14 August 2002, the Hilltop Flower site was completed on 19 November 2002, and the Brand flower site was completed on 4 December 2002. Soil samples were collected from each plot at all 3 sites approximately 3 weeks following the final fumigant application. These soil samples were used to determine population levels of Pythium sp., Phytophthora sp., and Fusarium sp. The Pyramid Flower site was planted with seedlings of Antirrhinum majus (snapdragon) 10 days after the final fumigant application. The Hilltop site was planted with seedlings of Liatris spicata cv callilepsis (gay-feather) on 30 December 2002. Problems arose with the Brand flower site and the only data collected were from the soil samples. Weed counts were made at the Pyramid and Hilltop sites and weeding times were measured for the Hilltop site. Stem rot, caused by Sclerotinia sclerotiorum occurred at the Hilltop site and disease counts were made. The results are presented in the figures that follow. The bars in the figures represent lease significant differences. No Phytophthora sp. were detected at Hilltop or Brand. Most treatments were significantly better than the control for the different parameters measured, but none of the treatments controlled malva, clover or groundsel. Phytophthora sp. and Pythium sp. were controlled better than Fusarium sp. Inline and Midas generally did a good job reducing pathogen populations, but did not reduce the severity of stem rot. More trials are being conducted to further test the efficacy of these fumigants.

Last Modified: 12/18/2014
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