Biochemical features of tomato under the influence of gibberellin and its impact on life table and physiology of Tuta absoluta (Merick) (Gelechiidae, Lepidoptera) reared on tomato

Abstract

The Tomato leaf miner Tuta absoluta is an important agricultural pest and exerts a considerable influence on tomato production across the world. In the present research tomato plants were sprayed with a gibberellin solution at a concentration of 50 µM. The gibberellin treatment resulted in a prolonged duration of T. absoluta preadult stage (33.67 days) compared to control group (27.38 days). The fecundity rate in treated females (82.33 eggs/female) was lowered compared to the controls (96.92 eggs/female). The intrinsic rate of increase (r) (0.080 day−1) was also reduced in treatments compared with the control (0.110 day−1). The finite rate of increase (λ) in treatment (1.084 day−1) decreased compared to the controls (1.116 day−1). The antioxidant system enzymes of T. absoluta, including catalase, peroxidase, and superoxide dismutase (SOD) were increased in treated insects. The gibberellin also increased the activity of detoxifying enzymes including Glutathione s-transferase with two substrates (DCNB and CDNB) and cytochrome P450 compared to the control group. While general esterase did not show significant differences in treatment and control. The secondary metabolites in treated plants including total sugar, total phenol content, anthocyanin, flavonoid and tannin showed an increasing trend. The results clearly show the negative impact of gibberellin on life table and physiology of the tomato leaf miner and can be considered favorable in integrated pest management programs of this pest.