Monitoring of resistance to pyrethroid and neonicotinoid insecticides of Aphis gossypii (Hemiptera : Aphididae)‎

Abstract EN

Resistance to several insecticides belonging to tow groups in the four field strains of the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae) collected from Behera, Dakahlia, Menofia, Skarkia and Beni-Suif Governorates during 2008-2010 at cotton seasons was investigated using slide-dipping method.

The insecticides used in this study belong to pyrethorids (Es-fenvalerate, deltamethrin, lambda-cyhalothrin, fenpropathrin, alphacypermethrin) and neonicotinoids (imidacloprid, acetamiprid, thiamethoxam).

The results indicated that the pyrethroid, deltamethrin recorded low levels of resistance during 2008- 2010 cotton growing seasons (Resistance ratio (RR) rang between 2.5-10.3-fold), but the other pyrethroids exhibited high levels of resistance in most of the field strains during 2008-2010 cotton growing seasons, lambda-cyhalothrin (RR rang between 9 - 44.7-fold), es-fenvalerate (RR rang between 2.9- 23.5-fold), fenpropathrin (RR rang between 5.6- 27.3- fold), alpha-cypermethrin (RR rang between 12.6 - 26-fold).

All tested neonicotinoids were still effective insecticides against most of field strains, where resistance levels were low or moderate during 2008-2010 cotton growing seasons (RR rang between 1.7-11.9-fold), except for thiamethoxam which showed high resistance in Dakahlia (RR 20.5-fold) in 2009 cotton growing season