Effect of different
temperature on the cotton leafworm Spodoptera littoralis Boisd (Lepidoptera: Noctuidae)
toxicity by insecticides and the biochemical responses measurements
El-Din Taha Hanan Salah
International Journal of Agricultural Sciences and
Veterinary Medicine;
Vol. 12(1); 16-22;
doi: https://doi.org/10.25303/1201ijasvm016022; (2024)
Abstract
The influence of post-treatment temperature on the toxicities of insecticides against
Spodoptera littoralis (Boisd.) larvae was evaluated in laboratory bioassays under
different temperatures sets and enzymes contents like beta glucosidase, mixed function
oxidase, lipase and the free amino acids. The thiamethoxam, imidacloprid, profenofos
and malathion LC50 values in ppm decreased by increasing temperatures degrees but
deltamethrin LC50 was slightly increased when temperature increased from 15 °C to
35 °C by 1.4 fold. Remarkably the toxicity increased with the temperature increase,
except for deltamethrin. All the tested insecticides were significantly have positive
correlation with temperature. Temperature coefficient were calculated for both one
and total increments.
Biochemical investigation of enzymes amount changes for thiamethoxam treatments
at two sublethal concentrations and different temperature established were measured.
MFO were generally increased at higher temperature and with increased concentrations.
But the total amino acids decreased with concentration increase at both temperatures
respectively and increased with temperature increase. The enzyme β-glucosidases
and lipases recorded highest activity at higher temperature and lower activity at
lower temperature of both thiamethoxam concentration respectively.
