Patterns of resistance to organophosphate insecticides in field populations of Helicoverpa armigera in Pakistan

✍ Scribed by Ahmad, Mushtaq; Iqbal Arif , M; Ahmad, Zahoor

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 90 KB
• Volume: 55
• Category: Article
• ISSN: 1526-498X
• DOI: 10.1002/(sici)1096-9063(199906)55:6<626::aid-ps988>3.0.co;2-l

✦ Synopsis

The pattern of organophosphate resistance in ®eld populations of Helicoverpa armigera (Hu È bner) was monitored in Pakistan from 1994 through 1997 using an IRAC leaf-dip method. Generally, moderate to high resistance was found to an orthophosphorate, monocrotophos and to a dithiophosphorate, ethion. Resistance to the commonly used thiophosphorates, chlorpyrifos and profenofos, was very low during 1994 and 1995 but showed an upward trend during 1996 and 1997. Resistance factors to the other thiophosphorates such as quinalphos, parathion-methyl, methamidophos and triazophos remained very low. Baseline lethal concentrations for ethion, methamidophos and triazophos were at least four to ®ve times higher than those for the other organophosphates tested, suggesting their low intrinsic ef®cacy against H armigera.