Invasive Species Compendium

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Abstract

Comparative toxicity of new insecticides generations against tomato leafminer Tuta absoluta and their biochemical effects on tomato plants.

Abstract

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 (LC50 = 0.26 and 0.46 mg L-1, respectively), followed by Radiant (Spinetoram), Vapcomic (Abamectin), and Challenger (Chlorfenapyr) (LC50 = 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.