Susceptibility of cotton whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) to diverse pesticides in Pakistan.

The cotton whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a serious pest of several summer crops in hot and dry climates. Its field populations (Asia II-1 biotype) were assessed for their susceptibility to diverse pesticides by using leaf-dip bioassay. There was no or a very low resistance to amitraz, hexythiazox, and pyridaben during 1992-2015. B. tabaci also exhibited no resistance to endosulfan during 1992-1997 and a very low resistance during 1998-2010, which then rose to a low level during 2011-2015. Chlorfenapyr resistance was very low during 1997-2008 and it reached to a high level during 2009-2011 and to a very high level in 2013 and 2015. Among avermectins, abamectin showed a very low resistance up to 2013 but a high resistance in 2015. Emamectin benzoate also demonstrated a very low resistance up to 2010, but a moderate-to-high resistance during 2011-2015. It may be concluded that the diverse chemistries, having novel modes of action and showing no, very low or low levels of resistance, can be substituted in rotation in the wake of resistance development to conventional insecticides.