EFFECTS OF TWO POTENTIAL PEST MANAGEMENT COMPONENTS, TIME OF SOWING AND SELECTIVE USE OF CHEMICALS FOR THE MANAGEMENT OF APHIDS (Lipaphis erysimi kalt)IN CANOLA CROP

A field study was conducted to evaluate seasonal aphid populatio n and efficacy of dijJerent insecticides,Nuvacron -10 SCW (Monocrotophos), Edmethyl 50EC (methy l Parathio n), Tamaran 500 SL (Methamedophos),Laser 25 EC (Cypermethrin + Dimethoa te), Confidor SL 20 (Imidacloprid) against aphids (Lipaphis erysimi kalt)in canola crop. Two expe riments, laid out in Randomized Complete Block Design (RCBD) with three replications,were conducted at Agricultural Research Institute, Tarnab, Peshawar during 2002-03. In the firs t expe riment, thecanola cultivar, BulbulO98 was sown on Z-differem sowing dates. The aphid inf estation per plant was highest i.e.2 16.10 aphids per plant on tr Nove mber, 2002, sowing dat e) , while the lowest inf estation i.e. 91.01 aphids perplant was recorded on (3rd Sep tember 2002, sowing date) . The early sown crop with lowest aphid populati onprovided highest y ield of200 1 kg ha , while the late sown crop with highest inf est ati on showed lowest y ield of605kg ha-I. In the second experiment, five insecticides were sprayed two times with an interval of 25 days against L.erysimi canola aphids sown on a separate plot. The minimum infestation per leaf was recorded in the range of 1.052.42,where Nuva cro n was pray ed. The maximum infestation among the trea ted pl ots was observed on Confidortreated plot i.e. in range of 4.1 9-5. 43 but Overall, all treated plots showed lesser inf estation as compared to theuntreated pots i.e. in the range of6.57-23.83 aphids per leaf after both sprays. All insecticides afte r l- day followedby 3-days showed good contro l and their effectiveness decre ased on I (jh and 15/h day s interval but still better thanthe untreated (chec k).