Pas photo entre l’efficacité comparative des deux insecticides.
CROSS RESISTANCE PATTERN FOR EMAMECTIN BENZOATE AND SYNTHETIC PYRETHROIDS IN DIAMONDBACK MOTH, PLUTELLA XYLOSTELLA (L.) (LEPIDOPTERA : PLUTELLIDAE)
Huma Nazir Kayani and Munir Ahmad*
Department of Entomology, PMAS-Arid Agriculture University Rawalpindi, Pakistan
Three pyrethroids (deltamethrin, bifenthrin and ג-cyhalothrin) and four new chemistry insecticides were tested against second instar larvae of Plutella xylostella under laboratory condition. Based on their LC50 values, deltamethrin was most toxic than ג-cyhalothrin and bifenthrin and among new chemistry insecticides, emamectin benzoate was the most toxic followed by acetamiprid, diafenthiuron and imidacloprid. Selection of two subpopulations for five generations with gradual toxic exposures of deltamethrin and emamectin showed decrease in survival rate. However, there was no drastic increase in LC50 values for both selected subpopulations than that of unselected subpopulation. Such high cross-resistance between emamectin benzoate with deltamethrin and ג-cyhalothrin suggest their wise use against this important insect pest. Rotational use of insecticides with different mode of action against P. xylostella might help avoiding development of resistance.