Screening of a Granular Chelate of Metham-Zinc for Nematicidal Activity Using Citrus and Root-knot Nematodes

A granular formulation of a chelate of metham-zinc (CMZ) which liberates the biocidal methyl isothiocyanate was tested for nematicidal activity on Tylenchulus semipenetrans in a jar soil screening and on Meloidogyne javanica (greenhouse test) and M. incognita (field test) infecting tomato. Comparisons were made with 1,3-D in the jar and pot experiments. The CMZ caused only 3.9% mortality of citrus nematode juveniles at 1.0 mug a.i./g soil, but 95.4% mortality at 10.0 mug a.i./g and 100.0% at 100.0 mug a.i./g. CMZ at 10.0 and 100.0 mug a.i./g significantly reduced tomato root infections by M. javanica in the pot test relative to the untreated control. In the field test, CMZ (11.5 g a.i./m(2) calibration rate) reduced M. incognita populations in the zone of incorporation but not below it, thus failing to provide season-long control for tomato. This material has good nematicidal activity at 10 mug a.i./g or more, but its effectiveness in the field may be limited by its lack of movement.