Agrotis ipsilon (Hufnagel), the black cutworm is a serious polyphagous underground pest. It has an economically important pest for many agricultural crops especially Potato plants which are attacked by the larvae in the early 4-6 pairs of growing leaves at that time. It must prevent the damage caused by this pest by effective control method (Abd-El-Aziz et al., 2019). That led to the intensive used of many pesticides which affected the environmental balance and pollution. Therefore, damaged public health through

The latent effects of three plant oils; namely thyme , bitter and neem on certain biological and biochemical parameters of the 6 th instar larvae of Spodoptera littoralis treated as 2 nd and 4 th instars with the LC 50 values of these oils. The results showed that the 2 nd instars were more susceptible to all the tested oils than the 4 th instar larvae. All treatments recorded significantly difference in all durations for both 2 nd and 4 th instars. Also, highly significant prolongation in pupal duration and the most prolonged oil was occurred by thyme on the 2 nd instars, while bitter was more effective on the 4 th instar larvae. Longevity of both sexes was reduced specially for male moths. No significant reduction was noticed on female longevity as a result of pretreated 2 nd but significant reduction was recorded for pretreated 4 th instars especially with thyme. Highly significant reduction in pupal weight produced from the treated 2 nd and 4 th larval instars with the three products. All oils caused deformations with various degrees for larvae, pupae and adults resulted from the treated 2 nd and 4 th instar larvae. The highest deformations exist in larval-pupa intermediate by thyme as pretreated 2 nd and 4 th of the larval instars. Bitter gave the highest pupal deformation as the pretreated 4 th instars followed by neem for the 2 nd and 4 th instars. Generally, all oils exhibited higher effect on the males. Total malformation during all generation recorded its maximum value with neem treatment as 2 nd instars then thyme was the most effective in both 4 th and 2 nd of the larval instars followed by bitter. Highly significant stimulation in chitinase and α-& β-esterases activity was recorded with all treatments and the most effective one caused by thyme followed by bitter. Highly significant inhibition in protease activity and acetylcholine esterase (AChE) was attained by (bitter & thyme) and (neem & thyme) oils, respectively. While high significant stimulation was recorded in protease and non significant stimulation of AChE was noticed by neem and bitter, respectively.

The effects of three new insecticides belonging to different groups on some enzyme activities of the 4 th instar larvae of Spodoptera littoralis were studied. The results proved that the three tested insecticides i.e. Indoxacarb, Emamectin benzoate and Pyridalyl inhibited all the enzymes. In this investigation, Indoxacarb was the most inhibitive of α-esterase and GST activities. Emamectin benzoate, resulted in pronounced inhibition of GOT, LDH. But , Pyridalyl induced significant stimulation of GPT, LDH and β-esterase.

No abstract

The present study aims to focus on the effect of the sublethal rates of Lambda-cyhalothrin +Thiamethoxam and Lambda-cyhalothrin, which belonging to groups 3 and 4 on the 4 th larval instar of Spodoptera littoralis field strain under laboratory conditions, and their effect on some physiological aspects, post-treatment with rates 50 and 100 ml/200L for 48 hrs. The results cleared that highly physiological disturbance was recognized as marked stimulating in total protein, total lipids, trehalase, AchE, and acid phosphatase synthesis however, inhibit amylase, invertase and alkaline phosphatase for lambda-cyhalothrin + Thiamethoxam. The tested sublethal rate of lambda-cyhalothrin, also be highly affected by stimulating total protein, invertase, trehalase, AchE, acid and alkaline phosphatases. On the other hand, inhibits total lipids and amylase synthesis in insect cells.