Study of resistance in Sitophilus oryzae against biosal, cypermethrin and phosphine on the basis of toxicity values
2008
Zafar, S.M.N. (Karachi Univ. (Pakistan). Dept. of Zoology) | Tariq, R.M. (Karachi Univ. (Pakistan). M.A.H. Qadri Biological Research Centre) | Aslam, M. (Karachi Univ. (Pakistan). Dept. of Statistics) | Breuer, M. (Department of Ecology, Frieburg (Germany). Enology Section) | Naqvi, S.N.H. (Baqai Medical Univ., Karachi (Pakistan). Dept. of Pharmacology) | Perveen, R. (Baqai Medical Univ., Karachi (Pakistan). Dept. of Pharmacology)
In the present work, the experiments were conducted for the resistance estimation in susceptible strain (SS), Karachi strain (KS) and Lahore stains (LS) of Sitophilus oryzae L. (Rice weevil). The three strains (populations) of S. oryzae were exposed to a neem formulation, Biosal (10 EC) available locally in the market, a synthetic pyrethroid, Cypermethrin (10 EC) and a fumigant Phosphine (PH3) used worldwide. The resistance was by filter paper impregnation contact method. The LD50 values were calculated by impregnated surface area as mug/cm2. The LC50 values of Biosal against three strains (populations) SS, KS & LS were computed as 18.600 471354 and 51.96 mug/cm2, respectively. Whereas the LC50 values of Cypermethrin against SS, KS and LS were computed as 29.08x10(4) 40.40x10(4) and 44.33x10(4) mug/cm2, respectively. While the LC50 values of Phosphine (PH3) against SS, KS and LS were computed as 0.166429, 0.698113 and 0.84574 g/2.8m3, resp ectively. Thus it may be concluded that, in three strains (populations), the increase in resistance may be shown as KS is less than LS. Whereas the toxicity (LD50) is in the following sequence, Biosal less than Phosphine and less than Cypermethrin. As a whole the Karachi (KS) and Lahore strain (LS) were compared with that of susceptible strain and both KS & LS were hound more resistant to Cypermethrin and Phosphine. Lahore strain was hound to be more resistant as compared 1o Karachi strain, but least or negligible resistance was found against Biosal (neem formulation = phytopesticide) which seems to be correct on the basis of LC50 values.
显示更多 [+] 显示较少 [-]