Control of insects in cotton crops in africa with some pyrethroid

Cotton yield results are presented for trials in Senegal, the Ivory Coast, Chad and Morocco in which the pyrethroids permethrin, biopermethrin, 3-phenoxybenzyl (1R,cis)-3-(2,2-dichlorovinyl)-2, 2-dimethylcyclopropanecarboxylate (NRDC 167) and (S)-α-cyano-3-phenoxybenzyl (1R,1 S)-cis,trans-3-(2,2-dibromovinyl-2, 2-dimethylcy-clopropanecarboxylate (NRDC 156) were compared with the compounds currently used for insect control. NRDC 156 gave marked yield increases at rates as low as 12.5 g.a.i./ha, the other pyrethroids needing higher rates to give comparable results. Control of mites, Hemitarsonemus lata and Tetranychus urticae was not satisfactory, however.