Effect of Azadirachta indica (Sapindales: Meliaceae) oil on Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae and adults

Authors

  • Jucelio Peter Duarte Universidade Federal do Rio Grande do Sul, Instituto de Biociências, Departamento de Zoologia, Porto Alegre, Rio Grande do Sul, 91.501-970, Brazil http://orcid.org/0000-0002-6781-7029
  • Luiza Rodrigues Redaelli Universidade Federal do Rio Grande do Sul, Instituto de Biociências, Departamento de Zoologia, Porto Alegre, Rio Grande do Sul, 91.501-970, Brazil
  • Simone Mundstock Jahnke Universidade Federal do Rio Grande do Sul, Instituto de Biociências, Departamento de Zoologia, Porto Alegre, Rio Grande do Sul, 91.501-970, Brazil
  • Samuel Trapp Universidade Federal do Rio Grande do Sul, Faculdade de Agronomia, Departamento de Fitossanidade, Porto Alegre, Rio Grande do Sul, 91.540-000, Brazil

Abstract

Azadirachta indica A. Juss. (Meliaceae) is used to control insects due to its compounds that have insecticidal, repellent, and antifeedant properties. These effects also may cause sublethal impacts on insects that reduce populations of target species. Such species can have economic importance, like Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), which feeds on various plant species. Thus, the objective of this study was to evaluate the larval mortality, lethal concentration, and sublethal effects on larvae, pupae, and adults of S. frugiperda after larvae were fed on an artificial diet containing A. indica oil at different concentrations. The oil was incorporated into the artificial diet at the concentrations of 5,000, 10,000, and 15,000 ppm, plus a control group. Four replicates of 35 second instar caterpillars were made for each treatment, and observed daily until pupation and emergence. The larval survival, duration of the larval and pupal periods, pupal weight and viability, wing length, and deformation of adults were evaluated. Longevity, fertility, and fecundity also were recorded for each pairing (mating arrangement) of males and females that developed on either a diet without oil and propanone, with propanone only, and with both oil and propanone. Azadirachta indica oil in the diet reduced survival and prolonged duration of the larval and pupal periods. Pupae in the groups that contained oil weighed less, and the adults had smaller wing length than in the control group. There was no influence on pupal viability, but the number of deformed adults increased. The oil reduced fecundity and longevity, but it did not alter fertility. These results suggest that the oil may reduce the probability of this insect remaining in the environment due to its ability to decrease the offspring and longevity of this species.

 

 

Resumo

Azadirachta indica A. Juss. (Sapindales: Meliaceae) é usada no controle de insetos devido a seus compostos que possuem atividade inseticida, de repelência e de deterrência alimentar. Esses efeitos também podem causar impactos subletais, reduzindo as populações de espécies-alvo. Espécies essas que podem ter importância econômica, como Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) que se alimenta de várias espécies de plantas. Assim, esse estudo teve como objetivo avaliar a mortalidade larval, concentração letal e o efeito subletal em larvas, pupas e adultos de S. frugiperda cuja larva se alimentou de uma dieta contendo óleo de A. indica em diferentes concentrações. O óleo foi incorporado, com propanona, em dieta artificial em concentrações de 5.000, 10.000, e 15.000 ppm, e o grupo controle. Quatro réplicas de 35 lagartas de segundo ínstar foram feitas para cada tratamento e observadas diariamente até a pupação e a emergência. Foram avaliados a sobrevivência larval, a duração da fase larval e pupal, o peso e a viabilidade pupal, o comprimento da asa e a proporção de adultos deformados. A longevidade, fertilidade e fecundidade também foram registradas para cada combinação de machos e fêmeas que se desenvolveram em dieta sem óleo e propanona, com somente propanona ou com óleo e propanona. O óleo de Azadirachta indica na dieta reduziu a sobrevivência e retardou a fase larval e pupal. As pupas dos grupos que continham óleo pesaram menos e os adultos tiveram um menor comprimento de asa do que os do grupo controle. Não houve influência na viabilidade pupal, mas o número de adultos deformados foi aumentado. O óleo reduziu a fecundidade e a longevidade, mas não alterou a fertilidade. Esses resultados sugerem que o óleo pode reduzir a probabilidade do inseto permanecer no ambiente devido a sua habilidade de diminuir a prole e a longevidade dessa espécie.

Key Words: development; fall armyworm; mortality; neem oil; reproduction

View this article in BioOne https://doi.org/10.1653/024.102.0218

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Published

2019-07-31

Issue

Vol. 102, No. 2 (June 2019)

Section

Research Papers

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