Effects of aqueous extracts of Dittrichia viscosa (Asteraceae) and insecticides on life history traits of Chaitophorus leucomelas (Insecta: Aphididae)

Methods used to control insect pests have been mainly chemical. Given the irritations associated with the use of pesticides, a search for alternatives is required, particularly through the use of plant extracts. The present study focused on comparing the insecticidal power of the aqueous extracts of the whole plant Dittrichia viscosa (commonly known as false yellowhead), the aqueous extract ratio of D. viscosa, and the bio-adjuvant Silene fuscata (1 : 1), as well as the synthetic pesticides Thiamethoxam/Lambda-cyhalothrin. Abundance, fecundity, demographic parameters, and biochemical parameters (lipid-glucidic biomarkers) of the winter phenotype of the black poplar leaf aphid Chaitophorus leucomelas were considered variables to assess the effectiveness of different approaches. The results show a strong effect of the aqueous extracts of D. viscosa (A.E. Plant) on abundance, with pronounced insecticidal activity from the aqueous extract ratio (A.E. Ratio) (P < 0.05). The lipid and carbohydrate energy of sexuparae undergo significant changes depending on the products used, with a disturbing effect of the synthetic product compared to aqueous extracts (P < 0.05). Fecundity shows a remarkable disturbance under the action of the active ingredient compared to the extracts. The results confirm that the products applied cause a disturbance in the growth rate (rm) and net reproductive rate (R0) of sexuparae, with the chemical treatment having the strongest effect (P < 0.05). The full dose of the active ingredient causes remarkable disturbances in the multiplication rate (λ) and the mean generation time (T) of the sexuparae compared to the other applied molecules. Some stability is reported for the doubling time (DT) of treated females compared to the control ones.