Survival and development of fall armyworm (Lepidoptera: Noctuidae) in weeds during the off-season

Authors

  • Tamara Moraes University of São Paulo, “Luiz de Queiroz” College of Agriculture, Department of Entomology and Acarology, P.O. Box 9, Piracicaba, São Paulo, 13418-900, Brazil
  • Alexandre Ferreira da Silva Embrapa Milho e Sorgo, P.O. Box 285, Sete Lagoas, Minas Gerais, 35701-970, Brazil
  • Natália Alves Leite University of Rio Grande do Sul, Department of Crop Protection, Porto Alegre, Rio Grande do Sul, 91540-000, Brazil
  • Décio Karam Embrapa Milho e Sorgo, P.O. Box 285, Sete Lagoas, Minas Gerais, 35701-970, Brazil
  • Simone Martins Mendes Embrapa Milho e Sorgo, P.O. Box 285, Sete Lagoas, Minas Gerais, 35701-970, Brazil

Abstract

The persistence and high dispersal of weeds during the off-season can favor the survival of pests and diseases that threaten cultivated crops in Brazil. The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is one of the principal polyphagous pests that takes advantage of the no-tillage system. Despite its pest status, little is known about S. frugiperda survival and development in alternative hosts, including those resistant to glyphosate. The purpose of this study was to investigate, in laboratory and greenhouse conditions, the adaptive capacity of S. frugiperda in volunteer maize and 6 weeds commonly found in Brazilian agroecosystems, including species with biotypes known for glyphosate resistance, such as fleabane, sourgrass, and goosegrass. We found that S. frugiperda survival and biomass were significantly higher in goosegrass, maize, and johnsongrass in both laboratory and greenhouse conditions. In contrast, fleabane, benghal dayflower, sourgrass, and smooth pigweed caused a decrease in S. frugiperda fitness. Along with S. frugiperda adaptive capacity, our results suggest that its persistence in the field can be directly related to weed control inefficiency during the off-season, increasing the demand for integrated pest and weed management.

 

Resumo

A persistência e a alta dispersão de plantas daninhas durante a entressafra podem favorecer a sobrevivência de pragas e doenças que ameaçam culturas cultivadas no Brasil. A lagarta-do-cartucho, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), é uma das principais pragas polífagas que tira proveito do sistema de plantio direto. Apesar de sua importância, pouco se sabe sobre a sobrevivência e o desenvolvimento de S. frugiperda em hospedeiros alternativos, incluindo aqueles resistentes ao glifosato. O objetivo deste estudo foi investigar, em condições de laboratório e casa-de-vegetação, a capacidade adaptativa de S. frugiperda em milho e 6 plantas daninhas comumente encontradas em agroecossistemas brasileiros, incluindo espécies com biótipos conhecidos pela resistência ao glifosato, como buva, capim-amargoso e capim-pé-de-galinha. Descobrimos que a sobrevivência e a biomassa de S. frugiperda foram significativamente maiores em capim-pé-de-galinha, milho e capim-massambará to sorgo selvagem, tanto em laboratório como em casa-de-vegetação. Por outro lado, buva, trapoeraba, capim-amargoso e amaranto causaram uma diminuição na aptidão de S. frugiperda. Além da capacidade adaptativa de S. frugiperda, nossos resultados sugerem que sua persistência no campo pode estar diretamente relacionada à ineficiência no controle de plantas daninhas durante a entressafra, sendo importante o manejo integrado de pragas e ervas daninhas.

Key Words: Spodoptera; glyphosate-resistance; fitness, biology; adaptive capacity

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Published

2020-07-10

Issue

Vol. 103, No. 2 (June 2020)

Section

Research Papers

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