Insecticidal doses of methyl iodide in foods and its residue.

100-105 g of food grains, oilseeds, nuts, dry fruits and processed foods were filled into glass jars and 30 3-4 wk old Tribolium castaneum adults introduced in the middle. Methyl iodide was introduced as a vapour, under a slight suction, exposure periods of 24 or 48 h being used. Tabulated data show the dosage required for 100% effect and the methyl iodide residue remaining in the food. Residues were as follows (ppm): red gram splits, 1.14; Bengal gram splits, 0.73; black gram splits, 0.43, green gram splits, 0.65; groundnut kernels, 0.22; groundnut meal, 0.45; cashew kernels, 2.2; walnuts, 0.96; almond kernels, 0.97; sesame seed, 1.19; coriander, 0.96; groundnut cake, 0.80; and coffee beans, 0.83. It therefore appears possible to utilize methyl iodide for fumigation of stored products, especially for in-package and rigid container treatments of processed foods, dry fruits, nuts and spices.