Abstract:

A preliminary investigation of the susceptibility of cowpea aphid to dichlorvos, cyhalothrin，phoxim and methomyl were performed in Jinjiang, Liangyuan, Yacheng and Tongshen villages, Hainan .province.The results showed that cowpea aphid from different areas had different susceptibility to dichlorvos, cyhalothrin，phoxim and methomyl. Cowpea aphid populations from Yacheng and Jinjiang villages were significantly resistant to cyhalothrin，phoxim, methomyl and dichlorvos, the resistant rates were 21.86-fold, 22.78-fold, 17.88-fold , 13.93-fold and 10.91-fold，12.59-fold, 11.47-fold, 13.49-fold as those of Liangyuan based on the results of LC50, respectively. The resistances of cowpea aphid from Tongshen village to cyhalothrin，phoxim, methomyl and dichlorvos were increased, its resistant rates were 1.58-fold, 12.27-fold, 4.45-fold and 2.28-fold as those of Liangyuan based on the results of LC50. Furthermore, the heterogeneity of the four cowpea aphid populations were better to cyhalothrin，phoxim, methomyl and dichlorvos. It’s time to beteer apply cyhalothrin，phoxim, methomyl and dichlorvos to control cotton ahpid in Hainan so as not to develop much more resistant cotton ahpid populations, respectively.