Influence of Grain Moisture and Storage Temperature on the Effectiveness of Five Insecticides as Grain Protectants1

Abstract

In a study of the influence of moisture content and storage temperature on the residual persistence and effectiveness of selected dosages of 5 insecticides in protecting stored grain against insects, the insecticides used and dosages applied in acetone solutions onto Ramona wheat included DDVP (diehlorvos)- 10 ppm; diazinon-10 ppm; Dibrom® (naled)-5 ppm; Guthion® O,O-dimethyl S-( 4-oxo-1,2,3-benzotriazin-3(4H)-ylmethyl) phosphorodithioate-5 ppm; and ronnel-15 ppm. The influence of moistme on insecticides, applied on wheat with a graded moisture range of 10%, 13%, and 16%, and stored at 60° F, was shown by reduced mortalities of the rice weevil, Sitophilus Oryzae (L.), and increased number of progeny with increases in moisture content of grain. Likewise, the influence of storage temperature on insecticides applied to wheat of 10% moisture content and stored at graded ranges of 60°, 70°, 80°, 90°, and 100° F was shown by reduced mortalities of the rice weevil and increased number of progeny with increases in storage temperature. Under the conditions of the study, residual effectiveness of insecticide treatments was in the order of diazinon>Guthion >ronnel>DDVP>Dibrom.