Insect herbivores associated with Nymphaea mexicana (Nymphaeaceae) in southern United States: potential biological control agents for South Africa

Potential biological control agents for South Africa

  • Megan Kim Reid Rhodes University, Department of Zoology and Entomology, Grahamstown, Eastern Cape 6140, South Africa;
  • Julie Angela Coetzee Rhodes University, Department of Botany, Grahamstown, Eastern Cape 6140, South Africa
  • Martin P Hill Rhodes University, Department of Zoology and Entomology, Grahamstown, Eastern Cape 6140, South Africa
  • Rodrigo Diaz Louisiana State University Agricultural Center, Department of Entomology, Baton Rouge, Louisiana 70803, USA
  • Lyn A Gettys University of Florida, Ft. Lauderdale Research and Education Center, 3205 College Avenue, Davie, Florida 33314, USA
  • James P Cuda University of Florida, Department of Entomology and Nematology, P.O. Box 110620, Gainesville, Florida 32611-0620, USA
  • Christopher S Reid Louisiana State University, School of Renewable Natural Resources, Baton Rouge, Louisiana 70803, USA;

Abstract

Nymphaea mexicana Zuccarini (Nymphaeaceae) (Mexican waterlily) is an emergent floating-leaved aquatic plant from the southeastern USA that is invasive in South Africa. In invaded waterbodies this plant restricts water movement, increases siltation, decreases recreational activities, and can deplete water oxygen levels, which in turn negatively impacts aquatic fauna. Currently there are no chemical, mechanical, or biological control programs in place for N. mexicana in South Africa, but the sustainability of biological control makes this the most desirable option. Field surveys for potential biological control agents were conducted in the native range of N. mexicana in Florida, Louisiana, and Texas from Aug to Oct 2018. Leaves, stems, flowers, and roots of N. mexicana were searched for insect herbivores by hand and using Berlese funnels. Insects were prioritized for use as biological control agents by considering the extent and type of feeding damage, field host range, and incidence (percentage of sites in which each species was found). In total, 15 confirmed species were found feeding on N. mexicana, and some taxa were identified only to family level. Incidence coverage estimator mean, MMRuns, Chao 2 mean, and Chao 2 upper 95% CI species accumulation estimators predicted that between 2 and 5 species were missed during the surveys. Based on field observations, Bagous americanus LeConte (Coleoptera: Curculionidae), and Megamelus toddi Beamer (Hemiptera: Delphacidae) were prioritized. Host specificity trials will be conducted to determine whether these insects may be used as biological control agents of N. mexicana.

Key Words: field surveys; Mexican waterlily; yellow waterlily; invasive alien plant

Resumen

Nymphaea mexicana Zuccarini (Nymphaeaceae) (Mexican waterlily) es una maleza acuática emergente nativa del sureste de Estados unidos, y considerada invasiva en África del Sur. En humedales invadidos, esta planta limita el movimiento de agua, incrementa sedimentación, decrece el valor recreacional, y puede reducir los niveles de oxígeno líquido, lo cual impacta negativamente la fauna acuática. No existe programas de control químico, mecánico o biológico para N. mexicana en África del Sur, pero la sostenibilidad del control biológico hace esta opción las más deseable. Desde Agosto a Octubre del 2018 se realizaron muestreos de campo para recolectar agentes de control biológico en el rango nativo de N. mexicana en Florida, Luisiana, y Texas. Insectos herbívoros de hojas, tallos, flores, y raíces de N. mexicana fueron buscados a mano o con embudos de Berlese. Insectos fueron priorizados para el uso como agentes de control biológico dependiendo del tamaño y tipo de daño, el rango de hospederos de campo, y su densidad de campo (porcentaje de sitios en los cuales la especie fue encontrada). Quince especies fueron encontradas alimentándose de N. mexicana, y posiblemente más están presentes debido a que taxones fueron identificados al nivel de familia. Los estimadores de especies acumulados media estimador de cobertura de incidencia, NMRuns, media Chao, y Chao por arriba del 95%, predijeron que entre dos y cinco especies no fueron encontradas durante los muestreos. Basado en observaciones de campo, Bagous americanus LeConte (Coleoptera: Curculionidae), y Megamelus toddi Beamer (Hemiptera: Delphacidae), fueron priorizados. Ensayos de especificidad serán realizados para determinar si esos insetos pueder se usados como agentes de control biológico de N. mexicana.

Palabras Clave: muestreos de campo; Ninfa Mexicana; Apapatla; planta invasive

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Author Biographies

Julie Angela Coetzee, Rhodes University, Department of Botany, Grahamstown, Eastern Cape 6140, South Africa

Deputy Director: Centre for Biological Control
Associate Professor of Botany

Martin P Hill, Rhodes University, Department of Zoology and Entomology, Grahamstown, Eastern Cape 6140, South Africa
Director: Centre for Biological Control Distinguished Professor and Head of Entomology 
Rodrigo Diaz, Louisiana State University Agricultural Center, Department of Entomology, Baton Rouge, Louisiana 70803, USA

Department of Entomology

Assistant Professor 

Lyn A Gettys, University of Florida, Ft. Lauderdale Research and Education Center, 3205 College Avenue, Davie, Florida 33314, USA
UF/IFAS Center for Aquatic and Invasive Plants

Assistant Professor 

James P Cuda, University of Florida, Department of Entomology and Nematology, P.O. Box 110620, Gainesville, Florida 32611-0620, USA

Department of Entomology and Nematology

Professor and Fullbright Scholar 

Christopher S Reid, Louisiana State University, School of Renewable Natural Resources, Baton Rouge, Louisiana 70803, USA;

School of Renewable Natural Resources

Instructor

PhD

Published
2020-04-15
Section
Research Papers