Presence of corn earworm and fall armyworm (Lepidoptera: Noctuidae) populations in sweet corn and their susceptibility to insecticides in Puerto Rico

Authors

  • Diego M Viteri University of Puerto Rico, Department of Agro-environmental Sciences, Isabela, 00662, Puerto Rico, USA
  • Angela M Linares University of Puerto Rico, Department of Agro-environmental Sciences, Lajas, 00667, Puerto Rico, USA
  • Irma Cabrera University of Puerto Rico, Department of Agro-environmental Sciences, Juana Díaz, 00795, Puerto Rico, USA
  • Leidy Sarmiento University of Puerto Rico, Department of Agro-environmental Sciences, Isabela, 00662, Puerto Rico, USA

Abstract

Corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), and fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), are important pests in sweet corn. Our objectives were to assess the occurrence of the Lepidopteran species affecting sweet corn in Puerto Rico, and to evaluate the efficacy of 9 insecticides to control larvae of corn earworm and fall armyworm. Spodoptera frugiperda was observed in all plant stages, whereas H. zea and Diatraea saccharalis (F.) (Lepidoptera: Crambidae) affected only ears. Larvae of corn earworm and fall armyworm were susceptible (mortality > 80% at 96 h) to Steinernema carpocapsae (Weiser) (Nematoda: Steinernematidae) + oil and to methomyl, respectively, whereas both species were susceptible to chlorpyrifos. The LC50 values for chlorpyrifos was 248 ppm, whereas 312,500 S. carpocapsae nematodes per L + 625 ppm of rapeseed oil caused 53% of larval mortality at 120 h post-treatment for corn earworm larvae.

 

Sumario

El gusano de la mazorca del maíz, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), y el gusano cogollero, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), son plagas de importancia económica en el maíz dulce. Los objetivos de esta investigación fueron identificar las especies de Lepidópteros que afectan el maíz dulce y evaluar la eficacia de 9 insecticidas para el control de las larvas del gusano de la mazorca y el gusano cogollero. Spodoptera frugiperda fue observado en todos los estados fenológicos del maíz mientras que H. zea y Diatraea saccharalis (F.) (Lepidoptera: Crambidae) afectaron solo las mazorcas. Las larvas del gusano de la mazorca y cogollero fueron susceptibles (mortalidad sobre el 80%) a Steinernema carpocapsae (Weiser) (Nematoda: Steinernematidae) + aceite y methomyl, respectivamente; mientras que las 2 especies fueron susceptibles a chlorpyrifos. Las CL50 para chlorpyrifos fue de 248 ppm, mientras que 312,500 nemátodos de S. carpocapsae por L + 625 ppm de aceite de colza causó 53% de mortalidad en larvas a las 120 h después de la aplicación para el gusano de la mazorca.

Key Words: Helicoverpa zea (Boddie); larval mortality; lethal concentrations; Spodoptera frugiperda (J. E. Smith); vegetative and reproductive stages

View this article in BioOne https://doi.org/10.1653/024.102.0228

Author Biography

Diego M Viteri, University of Puerto Rico, Department of Agro-environmental Sciences, Isabela, 00662, Puerto Rico, USA

Agro-environmental sciences Department

Assistant Professor

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Published

2019-08-01

Issue

Vol. 102, No. 2 (June 2019)

Section

Scientific Notes

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