Estudo fitoquímico e atividade inseticida de composição fitossanitária de Annona squamosa L. e Annona mucosa (Jacq.) Baill. (Annonaceae) para o controle de Plutella xylostella (L., 1758) (Lepidoptera: Plutellidae)

Abstract

Aiming to investigate the insecticidal potential of the Annonaceae family as an alternative control tactic for the integrated management of the diamondback, Plutella xylostella (Lepidoptera: Plutellidae), the research aimed to develop phytosanitary formulations from a stable emulsifiable formulation of the hexane extract of Annona squamosa L. and Annona mucosa (Annonaceae) ethanolic extract, evaluate their organoleptic characteristics, analyze long and short term stability, estimate lethal concentrations (LC50 and LC99) and evaluate the insecticidal activity in the capacity of oviposition, in the larval stages, to evaluate the persistence of the extract and of the emulsifiable formulation in the semi-field and to carry out the prospection of the chemical constituents. The estimation of LC50 and LC99 was determined using the Bliss formula (1934) performed by Probit analysis. For A. squamosa of the five samples tested of the emulsion of the hexanic extract of A. squomosa (EHAS) only emulsion 5 showed stability and appropriated along the short and long duration tests to be used as an insecticidal product; the estimated LC50 and LC99 of EHAS were 2.76 and 21.52 μL.mL-1, respectively, showing toxicity to P. xylostella; the LC99 of the EHAS presents ovicidal and repellent effect for oviposition; the LC50 and LC99 of the EHAS show efficiency in the 1st instar larval stage, however, they decrease the toxicity in the other instars; the persistence of EHAS toxicity in semi-field leaf spot condition is up to 18 and 16 days for CL50 and CL99, respectively, while semi-field in whole plant condition is 16 days for CL50 and CL99; the FACT and FH partitions were toxic to P. xylostella; through the analyzes by CLAE-DAD, the possibility of acetogenins, among them the squamocin in EHAS, is evidenced by the concentration of the area (%) and the wavelength (λ). For A. mucosa the LC50 and LC99 of the ethanolic extract of A. mucosa (EEAM) estimated were 51.64 and 616.2 μL.mL-1, respectively; the eeg LC99 shows ovicidal, oviposition repellent and efficiency effects in the 1st instar larval stage; eeg LC50 has ovicidal effect and efficiency in the 1st instar larval stage; the persistence of EEA toxicity shows residual effect of up to 8 and 12 days for LC99 and LC50, respectively, in semi-field condition with detached leaf and with whole plant is of up to 6 and 12 days for LC99 and LC50, respectively; the FHAL, FACT and FCLF partitions were the most toxic on P. xylostella; through the analysis by CLAE-DAD, the possibility of acetogenins, among them the squamocin in EHAM and alkaloids, is evidenced by the concentration of the area (%) and the wavelength (λ) and the presence of flavonoids orientin and rutin. It is concluded that the species of A. squamosa and A. mucosa present biopesticide action for the control of P. xylostella.