EVALUATION OF METHYL-IODIDE AS A SOIL FUMIGANT IN CONTAINER AND SMALL-FIELD PLOT STUDIES

Methyl iodide was evaluated as a soil fumigant as a potential replacem ent for the widely used soil fumigant methyl bromide. In container tri als, methyl iodide was significantly more effective than methyl bromid e against the plant parasitic nematodes Meloidogyne incognita, Heterod era schachtii and Tylenchulus semipenetrans and the plant pathogenic f ungus Rhizoctonia solani. In small field plots, soil populations of ro ot-knot nematodes were no longer detected after methyl iodide fumigati on at an application rate of 112 kg ha(-1). However, after growing a s usceptible lima bean host for two months, substantial root-knot gallin g occurred, while Rhizobium nodulation was absent. At 168 kg ha(-1) of methyl iodide, root-knot galling was reduced to less than 1%, and no Pythium propagules were recovered on selective detection media. These efficacy data support the conclusion that methyl iodide is a likely ca ndidate for replacing methyl bromide as a soil fumigant. (C) 1998 SCI.