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United States Department of Agriculture

Agricultural Research Service

Title: Drip Application of Alternative Fumigants to Methyl Bromide for Strawberry Production in California.

Authors
item Ajwa, Husein - UC DAVIS
item Trout, Thomas

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 26, 2004
Publication Date: February 3, 2004
Citation: Ajwa, H.A., Trout, T.J. 2004. Drip application of alternative fumigants to methyl bromide for strawberry production in california.. Hortscience.

Interpretive Summary: Strawberry is a high-value cash crop in California that benefits from pre-plant soil fumigation with methyl bromide (MB) and chloropicrin (CP). Methyl bromide will be banned in the U.S. and other developed countries by 2005 for most uses. Potential alternative chemicals to replace methyl bromide for soil fumigation include CP, 1,3-dichloropropene (1,3-D), and methyl isothiocyanate (MITC) generators such as metam sodium (MS). Commercial products of these fumigants applied singly and in combination through drip irrigation systems were evaluated at two sites for three consecutive growing seasons as alternatives to MB:CP fumigation for strawberry production in California. Strawberry growth, fruit yields, disease pressure, and weed biomass were compared to untreated control and shank injection with MB:CP mixture (67:33). For soils high in pathogen populations, fruit yield from the untreated plots was 34 to 50% relative to the MB:CP treatment. The greatest (95-110%) yields relative to MB:CP were in the high rates of the InLine treatments. Yields from simultaneous drip fumigation with a combination of Vapam HL and InLine or CP EC were less (67 to 79%) than yields from shank fumigation with MB:CP due to hydrolyses reactions in the irrigation water that reduced the efficacy of these combinations to control soil-borne pathogens. Application of reduced rates of InLine or CP EC followed six days later with reduced rates of Vapam HL controlled soil borne pathogens and weeds and produced good fruit yields. Alternative registered fumigants InLine and chloropicrin and these fumigants followed by metam sodium can produce strawberry yields equal to yields with methyl bromide:chloropicrin under the growing conditions in these trials.

Technical Abstract: Strawberry (Fragaria X ananassa Duchesne) is a high-value cash crop in California that benefits from pre-plant soil fumigation with methyl bromide (MB) and chloropicrin (CP). Methyl bromide will be banned in the U.S. and other developed countries by 2005 for most uses. Potential alternative chemicals to replace methyl bromide for soil fumigation include CP, 1,3-dichloropropene (1,3-D), and methyl isothiocyanate (MITC) generators such as metam sodium (MS). Commercial formulations of these fumigants applied singly and in combination through drip irrigation systems were evaluated for three consecutive growing seasons as alternatives to MB:CP fumigation for strawberry production in California. A mixture of 1,3-D and CP was shank injected as Telone C35' (62% 1,3-D and 35% CP) at 374 kg ha-1. An emulsifiable concentrate (EC) formulation of 1,3-D and CP was applied as InLine' (60% 1,3-D and 32% CP) at 236 and 393 L.ha-1 through drip irrigation systems in three amounts of irrigation water (25, 45, and 60 L.m-2). Chloropicrin (CP EC, 95%) singly was drip applied at 130 or 200 L.ha-1. Metam sodium was applied singly as Vapam HL' in three amounts of water and in combination with InLine and CP EC. Strawberry growth, fruit yields, disease pressure, and weed biomass were compared to untreated control and shank injection with MB:CP mixture (67:33) at 425 kg.ha-1. For soils high in pathogen populations, fruit yield from the untreated plots was 34 to 50% relative to the MB:CP treatment. The greatest (95-110%) yields relative to MB:CP were in the high rates of the InLine treatments. Yields from simultaneous drip fumigation with a combination of Vapam HL and InLine or CP EC were less (67 to 79%) than yields from shank fumigation with MB:CP due to hydrolyses reactions in the irrigation water that reduced the efficacy of these combinations to control soil-borne pathogens. Application of reduced rates of InLine or CP EC followed six days later with reduced rates of Vapam HL controlled soil borne pathogens and weeds and produced greatest fruit yield relative to all treatments.

Last Modified: 8/1/2014
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