Abstract:

[Objectives] To investigate the effect of deltamethrin on the growth, development and energy storage of 1st instar nymphs of Acyrthosiphon solani Kaltenbach and thereby provide a theoretical basis for research pesticide resistance mechanisms in this pest. [Methods] First instar nymphs of A. solani were treated with an LC₅₀ dose of deltamethrin via the impregnation method after which the growth of successive instars was monitored every 12 h. In addition, the protein, carbohydrate and total lipid of each nymph was measured by staining these with anthrone, coomassie brilliant blue G-250 and vanillin, respectively. [Results] We found that deltamethrin significantly extended the growth period of 1st and 2nd instar nymphs by 1.44 times and 1.26 times, respectively (P < 0.05). There was also a significant difference in the specific gravity of protein between treatment and control groups in 2nd (0.74 times), 3nd (0.69 times) and 5th instar (1.17 times) nymphs. The protein content of other treated instars also differed from their respective control group, but not significantly. There was also a significant difference in the specific gravity of soluble carbohydrate between 2nd instar treatment and control groups (1.39 times). Glycogen differed significantly between treatment and control groups in the 1st (3.81 times) and 2nd instars (3.82 times). Finally, total lipid content significantly differed between the treatment and control groups of all four instars; treatment groups having 2.04, 1.34, 1.25 and 1.30 times the total lipid content of their respective control groups. [Conclusion] An LC₅₀ dose of deltamethrin effects both the growth and nutrient content of all instars of A. solani.

Key words: Acyrthosiphon solani, lethal concentration, deltamethrin, instar sduration, energy substances