Fumigant Alternatives to Methyl Bromide for Polyethylene-mulched

Abstract

<jats:p>Tomato (<jats:italic>Lycopersicon esculentum</jats:italic> Mill.) was grown to evaluate various chemicals as possible alternatives to methyl bromide soil fumigation. Due to a combination of weeds, nematodes, and soil fungi, the use of a broad-spectrum fumigant has been essential for economical tomato production in Florida. Methyl bromide (MBr) and combinations of MBr with chloropicrin (Pic) are the fumigants of choice for most growers using polyethylene mulch culture. In 1991, MBr was allegedly associated with stratospheric ozone depletion. The U.S. Environmental Protection Agency has since mandated a phaseout of MBr for soil fumigation in the United States by the year 2001. At three locations in Florida, alternative soil fumigants were evaluated, including soil injected 98% MBr—2% Pic at 450 kg·ha<jats:sup>-1</jats:sup>, 67% MBr—33% Pic (390 kg·ha<jats:sup>-1</jats:sup>), Pic (390 kg·ha<jats:sup>-1</jats:sup>), dichloropropene + 17% Pic (1,3-D + Pic) at 327 L·ha<jats:sup>-1</jats:sup>, and metam-sodium (935 L·ha<jats:sup>-1</jats:sup>). Also, metam-sodium and tetrathiocarbonate (1870 L·ha<jats:sup>-1</jats:sup>) were applied by drip irrigation. Dazomet (450 kg·ha<jats:sup>-1</jats:sup>) was surface applied and soil incorporated. Pebulate (4.5 kg·ha<jats:sup>-1</jats:sup>) was soil incorporated with some treatments. Pic and 1,3-D + Pic treatments provided good to moderate control of nematodes and soil fungi except in one of the six studies, in which nematode control with 1,3-D was moderate to poor. Nutsedge densities were suppressed by addition of pebulate. Tomato fruit yields with 1,3-D + Pic + pebulate and with Pic + pebulate at the three sites ranged from 85% to 114%, 60% to 95%, and l01% to 119%, respectively, of that obtained with MBr treatments. Pest control and crop yield were lower with treatments other than the above pebulate-containing or MBr-containing treatments. These studies indicate that no one alternative pesticide can provide the consistent broad-spectrum control provided by MBr. Chemical names used: trichloronitromethane (chloropicrin); 1,3-dichloropropene (1,3-D); sodium N-methyldithiocarbamate (metam-sodium); sodium tetrathiocarbonate (tetrathiocarbonate); 3,5-dimethyl-(2<jats:italic>H</jats:italic>)-tetrahydro-l,3,5-thiadiazine-2-thione (dazomet); S-propyl butyl(ethyl)thiocarbamate (pebulate).</jats:p>

Transplanted Pepper (Capsicum annuum) Tolerance to Selected Herbicides and Method of Application

“…While alternative fumigants are being investigated, none provide the broad-spectrum weed control of MBr (Csinos et al, 1997;Lacascio et al,1997Lacascio et al, , 1994. Csinos et al (1997) suggested using combinations of pesticides to maximize the benefit of each product to target the broad-spectrum of pests (weeds, nematodes, fungi, etc.)…”

Soil Fate of Agricultural Fumigants in Raised-Bed, Plasticulture Systems in the Southeastern United States

“…Dimethyl disulfide (DMDS) is undergoing registration approval. When coapplied using good agricultural practices (GAPs), these fumigants can achieve a spectrum of pest and disease control similar to methyl bromide while maintaining a high level of marketable yields (Ajwa et al, 2002; Chellemi and Mirusso, 2004, 2006; Gilreath et al, 1999; Locascio et al, 1997; Noling and Gilreath, 2000). Good agricultural practices include improved application methods and technology, reduced application rates, and selective inclusion of specific soil edaphic and environmental conditions.…”

Plant Health Management: Soil Fumigation

“…Ranked in order of impact on the retention of fumigants in the soil are soil water content, soil tilth, the type of plastic film, and soil texture . When GAPs are following during the fumigant application process, many soil fumigants can achieve a spectrum of pest control similar to methyl bromide while maintaining a high level of marketable yields (Ajwa et al, 2002;Chellemi and Mirusso, 2006;Gilreath et al, 1999;Locascio et al, 1997;MacRae et al, 2010). By definition, soil disinfestation procedures are not sustainable because reinfestation of treated soil occurs during crop production, necessitating the reapplication of soil disinfestation procedures for future crops.…”