Methyl bromide alternatives for presowing fumigation in tobacco seedling production

This study aimed to evaluate the effects of soil fumigant alternatives to methyl bromide (MeBr) on the weeds, damping-off, and seedling growth of tobacco. Methyl bromide (90 g m^-2), dazomet (D) (50 g m^-2), and metam sodium (MS) (100mLm^-2) were evaluated in 2 locations in the Karacasu district of Aydın province, Turkey, February-April 2005. In addition, half doses of D and MS were investigated in 2006. MeBr treatment had 52.5% control against the postemergence damping-off caused by Pythium spp., while alternative treatments had no effect on the disease in 2005. In 2006, MeBr and MS (100 mL m^-2) showed 77.6% and 100% control against the disease, respectively. All fumigant treatments significantly controlled pigweed species (Amaranthus spp.), common purslane (Portulaca oleracea L.), common lambsquarters (Chenopodium album L.), nettleleaf goosefoot (Chenopodium murale L.), burning nettle (Urtica urens L.), and large crabgrass (Digitaria sanguinalis (L.) Scop.), except dazomet (50 gm^-2) on pigweed (86.2%), common lambsquarters (68.6%), nettleleaf goosefoot (60.5%), and burning nettle (64.3%) at one location in 2005. Similarly, all fumigants, including low doses ofMS (50 mL m^-2) and D (25 g m^-2), significantly decreased the populations of pigweed species, common purslane, common lambsquarters, prostrate knotweed (Polygonumaviculare L.), and sowthistle species (Sonchus spp.) in 2006. Tobacco (cv. Akhisar) seedling height and fresh weight increased significantly with treatments of MeBr, MS (100 mL m^-2), and D (50 g m^-2) at the 2 locations in both years.