Insecticidal Residues in Milling Fractions from Wheat Treated with Methoxychlor, Malathion, and Lindane1

Milling tests were conducted to determine the insecticide residue in flour derived from wheat to which three candidate protective treatments had been applied as dusts or sprays at several rates. Some lots were milled 9 to 10 days after treatment and others after aging 18 to 24 months. Samples analyzed were the wheat just before and after cleaning, and the flour, bran, shorts, and germ. In most cases, cleaning removed only a small amount of insecticide. The highest residues were in the bran and shorts. Very little insecticide carried over into the flour, 0 to less than 0.3 p.p.m. from malathion applied at 2.5 to 7.5 p.p.m.; 0.3 to 1.8 p.p.m. from methoxychlor applied at 5 to 50 p.p.m.; and 1.3 to 2.6 p.p.m from lindane applied at 2.5 to 7.5 p.p.m.