The persistence and activity of permethrin and chlorpyrifos-methyl sprays on jute and woven polypropylene bags

To simulate the treatment of commercial bags, the persistence and biological activity on jute and woven polypropylene sheets of permethrin emulsifiable concentrate, were studied. The residues produced in wheat grains under the sprayed sheets were also determined. Residues were analysed by gas-liquid chromatography, and bioassays with Tribolium confusum Duv. on the treated materials.The insecticide residues were of shorter persistence on jute than on polypropylene sacking material. However, higher residues were found in the grain under jute than under polypropylene bags. Permethrin was found more effective for beetle control and resulted in less residue in the grain than chlorpyrifosmethyl. Polypropylene covering provided more protection to the wheat against insect and insecticide penetration as compared with jute covering.