Yellow Nutsedge (Cyperus esculentus) Control with Methyl Iodide in Combination with Totally Impermeable Film

Abstract

Methyl bromide (MBr) has been an industry standard for soil fumigation in a multitude of crops for decades. However, it has been banned by the United Nations Environment Programme, and alternatives to MBr must be implemented to sustain productivity in many vegetable crops that depend on soil fumigation. One alternative that has been implemented in some areas is methyl iodide (MeI). Efficacy of MeI has been demonstrated on many pest species and has been generally similar to MBr. Methyl iodide is a costly material, which has likely limited its adoption. Virtually impermeable film (VIF) and totally impermeable film (TIF) provide greater fumigant retention than low-density and high-density polyethylene film, which can allow for reduced fumigant application rates while maintaining fumigant efficacy. The objectives of this research were to evaluate TIF with reduced rates of shank-applied MeI : chloropicrin (Pic) (50 : 50 w/w) for the control of yellow nutsedge in tomato. Treatments included a standard rate of MeI : Pic (93.3 L ha−1[178 kg ha−1broadcast]) under VIF and TIF, three reduced rates (37.3, 56, 74.6 L ha−1[71.2, 106.8, 142.5 kg ha−1broadcast, respectively]) under TIF, and a nontreated control under TIF. Results indicate fumigant use rates may be reduced from a standard 93.3 L ha−1under VIF to 37.3 L ha−1(60% reduction) under TIF while providing yellow nutsedge control and maintaining tomato yields.