The Impact of Metam Sodium on Nutsedge Control Provided By Dimethyl Disulfide.

Many vegetable producers utilize soil fumigants to manage soil-borne pests such as weeds, nematodes, and diseases. Since the phase out of methyl bromide there has been a continual search for strategies to improve the flexibility and efficacy of currently available fumigants. One of the more recently registered soil fumigants in the United States, dimethyl disulfide (DMDS), has shown good efficacy on a broad spectrum of soil-borne pests when mixed with chloropicrin (Pic). This combination has been deployed on substantial acreage in Florida in recent years. There are efforts in registering DMDS globally, including Mexico and the European Union. However, the combination of DMDS and Pic has some limitations on a global scale because of the restrictions on Pic use in a number of countries. For this reason research was conducted to investigate combinations of DMDS with metam sodium (MS) for efficacy on soil-borne pests. Two rates of MS (40 and 50 gal ac^-1) were used alone or in combination with a single rate of DMDS (34 gal ac^-1) and compared with a non-treated control and a mixture of DMDS and Pic (40 gal ac^-1). All fumigants were applied in raised beds covered with totally impermeable film mulch. When DMDS and MS were applied alone, nutsedge populations were not significantly different than the non-treated control. When DMDS and MS were applied in combination, nutsedge populations were significantly lower than the non-treated control and similar to the DMDS Pic mixture. These data indicate that the combination of DMDS and MS may be an effective alternative to DMDS Pic in regions where Pic use is prohibited or limited in availability.