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Background: The physico-chemical properties along with the insecticidal potency of seven non-traditional insecticides from different classes compared with three conventional insecticides were assessed versus Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) below laboratory and field conditions. Results: All non-conventional insecticides passed the physico-chemical properties except Actra (thiamethoxam) which failed in pH test. Moreover, all conventional insecticide failed these characteristics. The laboratory assessment of the examined insecticides demonstrated that Emperor (Emamectin benzoate) and Coragen (Chlorantraniliprole) were the most superior (LC 50 = 0.26 and 0.46 mg L −1 , respectively), followed by Radiant (Spinetoram), Vapcomic (Abamectin), and Challenger (Chlorfenapyr) (LC 50 = 0.59, 0.60, and 24.07 mg L −1 , respectively). Accordingly, these most potent insecticides were evaluated under field circumstances. The levels of insect infestation reduced by 98.74 and 95.51% after 7 days of spraying for the most effective insecticides, Emperor and Coragen, respectively, while the other examined insecticides were at par with one another. Concerning the biochemical effects of the most potent insecticides on tomato plants, all treatments induced promising effect on the photosynthetic pigments. In addition, they significantly minimized the activity of the enzymatic and non-enzymatic antioxidants. The most potent biochemical effects were ascribed to Emperor and Coragen insecticides. These two insecticides proved again the maximum total and marketable yields. Moreover, Challenger, Radiant, and Vapcomic revealed minor differences with Emperor and Coragen of the efficiency and marketable yield. Conclusions: The results proved that the examined insecticides, Challenger, Radiant, Vapcomic, especially, Emperor and Coragen can be successfully used in the IPM tactic against T. absoluta insect.

Fourth instar larvae of cotton leafworm, Spodoptera littoralis (Boisd.), fed on castor bean leaves treated with sub-lethal concentrations of both alcohol and hexane extracts of Egyptian conyza and Challenger 36% SC insecticide as well to study their effects on mortality, food consumption and utilisation of food. The tested insecticides exhibited relatively high mortality in alcoholic extract of Egyptian conyza (5.0% concentration) followed by Challenger (1.0% concentration). Results showed a slight reduction in the consumption index for larvae treated with both alcoholic extract and Challenger at low concentrations, while hexane extract (5%) recorded significant increase. The approximate digestibility (AD) was reduced in all treatments of alcoholic extract and the relative growth rate insignificantly decreased at 5% concentration, whereas AD increased for larvae fed on Challenger 0.25% concentration. The lower concentration of alcoholic extract of conyza and all treatments of Challenger pesticides induced insignificant decrease in the efficiency of conversion of the ingested food, while hexane extract exhibited insignificant increase. Challenger at all tested concentrations achieved insignificant decrease in the efficiency of the conversion of digested food with respect to the control.

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The effect of Artemisia monosperma wild plant hexane extract on some biological and physiological aspects of Spodoptera littoralis, as well as some biochemical and histopathological changes after treatment with this extract have been studied. The results indicated that treatment with larvae for two days revealed satisfactory effects in larval mortality (50%) and in larval weight and prolonged the effect in the pupal stage. Also the treatment reduced the food consumption and the amount of faeces of the tested larvae which led to a significant reduction in the final body weight with 76.4%. Treatment also extended the time of food passage through the midgut to 3.2 h compared to 1.38 h in control, and the larvae had a smaller midgut. The enzymatic activity of the digestive enzymes amylase and invertase revealed a significant inhibition in the treated larvae. Also transaminase enzyme activity (AST and ALT) reduced after treatment. The results of phosphatase enzyme activity (ACP and ALP) showed a potent inhibitory effect on both enzymes which more was pronounced in ALP than ACP activity, the percent inhibition being 73.8% and 30.6%, respectively. The histopathological effects of A. monosperma treatment on the midgut of Spodoptera littoralis revealed that the epithelium membrane was exfoliated and completely destroyed. Meanwhile, epithelia cells were strongly vacuolated and considerably elongated. Boundary lines between the cells disappeared.