Toxicities of some traditional insecticides;
were examined on 2nd and 4th instars of both laboratory
and field strain of Spodoptera littoralis (Boisd.) under
laboratory conditions. Examined insecticides exhibited
toxicities on laboratory strain greater than field strain.
LC50 values on 2nd instar of laboratory strain were 0.224,
0.885, 1.033, 12.017, 24.723 and 35.171 ppm for Speedo®
, and Reldan®
respectively. Regarding field strain, the values were
0.391, 2.891, 7.076, 28.262, 30.675 and 45.565 ppm in the
same manner. All treatments decrease activities of
acetylcholine esterase (AChE) compared with control.
Similarly, they exhibited a decrease in α and β-esterases
(CE) of larval homogenates lower than control.
Glutathione-S-transferase (GST) displayed activities in
field strain and laboratory strains greater than control.
In field strain, the activities were 22.50, 15.00, 16.50,
15.50, 14.00 and 20.50 nM/mg/min for Rider®
, and Grand®
, respectively. In
the same manner, Aspartate aminotransferase (AST)
and alanine aminotransferase (ALT) of treated insects
displayed activities greater than control. Esterases and
GST enzymes may provide a primary investigation
concern insect resistance and/or susceptibility to
Keywords : Insecticides; Spodoptera littoralis; AChE; Esterases; GST.