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Title: Invertebrate fauna associated with Torpedograss, Panicum repens (Cyperales: Poaceae), in Lake Okeechobee, Florida, and prospects for biological control

Abstract

Torpedograss, Panicum repens L., is an adventive, rhizomatous grass species that has become an invasive weed of terrestrial, wetland, and aquatic environments in tropical and subtropical regions worldwide. Until recently, strategies for controlling torpedograss in the USA have focused almost exclusively on mechanical and chemical methods, either alone or in combination, with varied results. A survey of the arthropods and nematodes currently associated with the plant in Lake Okeechobee, Florida, was conducted as part of a feasibility study to determine whether torpedograss is an appropriate target for a classical biological control program. Overall, approximately 4,000 arthropods and 400 nematode specimens were collected. Sweep, clipped vegetation, and soil core samples were dominated by representatives of the arthropod orders Hemiptera, Hymenoptera, Diptera, and Acari. Lesion nematodes of the genus Pratylenchus were commonly associated with the roots of torpedograss. None of the organisms collected were torpedograss specialists. Although classical biological control of torpedograss is feasible based on the extent of the infestation, economic losses, resistance to conventional controls, and the report of a potentially host specific natural enemy in India, the botanical position of this grass weed will require a formal risk assessment before proceeding with a classical biological control program. (author) [Spanish]more » La conota, Panicum repens L., es una especie foranea de pasto que produce rizomas que ha convertido en ser una maleza invasora de ambientes terrestres, pantanosos y acuaticos en regiones tropicales y subtropicales en todo el mundo. Hasta hace un tiempo reciente, las estrategias para controlar conota en los EEUU eran enfocadas casi exclusivamente en los metodos mecanicos y quimicos, solos o en combinacion, con resultados variables. Un muestreo de los artropodos y nematodos asociados corrientemente con esta planta en el Lago de Okeechobee, Florida, fue realizado como parte de un estudio de factibilidad para determinar si conota es una candidata apropiada para un programa de control biologico clasico. En general, especimenes de aproximadamente unos 4,000 artropodos y unos 400 nematodos fueron recolectados. Muestras recolectadas pasando una red sobre vegetacion mezclada, cortando la vegetacion y tomando centros del suelo fueron dominados por representantes de artropodos de los ordenes de Hemiptera, Hymenoptera, Diptera, y Acari. Nematodos en el genero Pratylenchus, que causan lesiones sobre tejido, fueron asociados regularmente con las raices de conota. Ninguno de los organismos recolectados eran especialistas sobre conota. Aunque el control biologico clasico de la conota es factible basado sobre la magnitud de la infestacion, las perdidas economicas, la resistencia hacia los metodos de control convencionales y el informe en la India de un posible enemigo natural especifico a esta planta, la posicion botanica de este pasto maleza requiere una evaluacion de riesgo economico formal antes de continuar con un programa de control biologico clasico. (author)« less

Authors:
; ;  [1]
  1. University of Florida, Entomology and Nematology Department, Gainesville, FL 32611-0620 (United States)
Publication Date:
OSTI Identifier:
20942935
Resource Type:
Journal Article
Resource Relation:
Journal Name: Florida Entomologist; Journal Volume: 90; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); DOI: 10.1653/0015-4040(2007)90[238:IFAWTP]2.0.CO;2; Refs, 3 tabs
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; DIPTERA; FEASIBILITY STUDIES; FLORIDA; GRAMINEAE; HEMIPTERA; HYMENOPTERA; LAKES; NEMATODES; PEST CONTROL; RISK ASSESSMENT; ROOTS; SOILS; WETLANDS

Citation Formats

Cuda, J.P., Dunford, J.C., and Leavengood, J.M. Jr. Invertebrate fauna associated with Torpedograss, Panicum repens (Cyperales: Poaceae), in Lake Okeechobee, Florida, and prospects for biological control. United States: N. p., 2007. Web. doi:10.1653/0015-4040(2007)90[238:IFAWTP]2.0.CO;2; REFS, 3 TABS.
Cuda, J.P., Dunford, J.C., & Leavengood, J.M. Jr. Invertebrate fauna associated with Torpedograss, Panicum repens (Cyperales: Poaceae), in Lake Okeechobee, Florida, and prospects for biological control. United States. doi:10.1653/0015-4040(2007)90[238:IFAWTP]2.0.CO;2; REFS, 3 TABS.
Cuda, J.P., Dunford, J.C., and Leavengood, J.M. Jr. Thu . "Invertebrate fauna associated with Torpedograss, Panicum repens (Cyperales: Poaceae), in Lake Okeechobee, Florida, and prospects for biological control". United States. doi:10.1653/0015-4040(2007)90[238:IFAWTP]2.0.CO;2; REFS, 3 TABS.
@article{osti_20942935,
title = {Invertebrate fauna associated with Torpedograss, Panicum repens (Cyperales: Poaceae), in Lake Okeechobee, Florida, and prospects for biological control},
author = {Cuda, J.P. and Dunford, J.C. and Leavengood, J.M. Jr.},
abstractNote = {Torpedograss, Panicum repens L., is an adventive, rhizomatous grass species that has become an invasive weed of terrestrial, wetland, and aquatic environments in tropical and subtropical regions worldwide. Until recently, strategies for controlling torpedograss in the USA have focused almost exclusively on mechanical and chemical methods, either alone or in combination, with varied results. A survey of the arthropods and nematodes currently associated with the plant in Lake Okeechobee, Florida, was conducted as part of a feasibility study to determine whether torpedograss is an appropriate target for a classical biological control program. Overall, approximately 4,000 arthropods and 400 nematode specimens were collected. Sweep, clipped vegetation, and soil core samples were dominated by representatives of the arthropod orders Hemiptera, Hymenoptera, Diptera, and Acari. Lesion nematodes of the genus Pratylenchus were commonly associated with the roots of torpedograss. None of the organisms collected were torpedograss specialists. Although classical biological control of torpedograss is feasible based on the extent of the infestation, economic losses, resistance to conventional controls, and the report of a potentially host specific natural enemy in India, the botanical position of this grass weed will require a formal risk assessment before proceeding with a classical biological control program. (author) [Spanish] La conota, Panicum repens L., es una especie foranea de pasto que produce rizomas que ha convertido en ser una maleza invasora de ambientes terrestres, pantanosos y acuaticos en regiones tropicales y subtropicales en todo el mundo. Hasta hace un tiempo reciente, las estrategias para controlar conota en los EEUU eran enfocadas casi exclusivamente en los metodos mecanicos y quimicos, solos o en combinacion, con resultados variables. Un muestreo de los artropodos y nematodos asociados corrientemente con esta planta en el Lago de Okeechobee, Florida, fue realizado como parte de un estudio de factibilidad para determinar si conota es una candidata apropiada para un programa de control biologico clasico. En general, especimenes de aproximadamente unos 4,000 artropodos y unos 400 nematodos fueron recolectados. Muestras recolectadas pasando una red sobre vegetacion mezclada, cortando la vegetacion y tomando centros del suelo fueron dominados por representantes de artropodos de los ordenes de Hemiptera, Hymenoptera, Diptera, y Acari. Nematodos en el genero Pratylenchus, que causan lesiones sobre tejido, fueron asociados regularmente con las raices de conota. Ninguno de los organismos recolectados eran especialistas sobre conota. Aunque el control biologico clasico de la conota es factible basado sobre la magnitud de la infestacion, las perdidas economicas, la resistencia hacia los metodos de control convencionales y el informe en la India de un posible enemigo natural especifico a esta planta, la posicion botanica de este pasto maleza requiere una evaluacion de riesgo economico formal antes de continuar con un programa de control biologico clasico. (author)},
doi = {10.1653/0015-4040(2007)90[238:IFAWTP]2.0.CO;2; REFS, 3 TABS},
journal = {Florida Entomologist},
number = 1,
volume = 90,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • The parasitoid Lipolexis oregmae Gahan (introduced as L. scutellaris Mackauer) was imported from Guam, evaluated in quarantine, mass reared, and released into citrus groves in Florida in a classical biological control program directed against the brown citrus aphid, Toxoptera citricida Kirkaldy. Releases of 20,200, 12,100, and 1,260 adults of L. oregmae were made throughout Florida during 2000, 2001, and 2002, respectively. To determine if L. oregmae had successfully established, surveys were conducted throughout the state beginning in the summer of 2001 and continuing through the summer of 2003. Parasitism during 2001 and 2002 was evaluated by holding brown citrus aphidsmore » in the laboratory until parasitoid adults emerged. Lipolexis oregmae was found in 10 sites in 7 counties and 4 sites in 3 counties with parasitism rates ranging from 0.7 to 3.3% in 2001 and 2002, respectively. Laboratory tests indicated that high rates of mortality occurred if field-collected parasitized aphids were held in plastic bags, so a molecular assay was used that allowed immature L. oregmae to be detected within aphid hosts immediately after collection. The molecular assay was used in 2003 with the brown citrus aphids and with other aphid species collected from citrus, weeds, and vegetables near former release sites; immatures of L. oregmae were detected in black citrus aphids, cowpea aphids, spirea aphids, and melon aphids, as well as in the brown citrus aphid, in 4 of 8 counties sampled, with parasitism ranging from 2.0 to 12.9%, indicating that L. oregmae is established and widely distributed. Samples taken in Polk County during Oct 2005 indicated that L. oregmae has persisted. The ability of L. oregmae to parasitize other aphid species on citrus, and aphids on other host plants, enhances the ability of L. oregmae to persist when brown citrus aphid populations are low. (author) [Spanish] El parasitoide Lipolexis oregmae Gahan (introducido como L. scutellaris Mackauer) fue importado de Guam, evaluado en cuarentena, criado en masa y liberado en huertos de citricos en un programa de control biologico clasico dirigido contra el afido pardo de citricos, Toxoptera citricida Kirkaldy. Se hicieron liberaciones de 20,200, 12,100, y 1,260 adultos de L. oregmae a traves de la Florida durante los anos de 2000, 2001, y 2002, respectivamente. Para determinar si L. oregmae ha logrado en establecer, se realizaron sondeos a traves del estado empezando en el verano del 2001 y continuando hasta el final del verano del 2003. El parasitismo durante 2001 y 2002 fue evaluado con el mantenimiento de individuos del afido pardo de los citricos en el laboratorio hasta que los adultos emergieron. Lipolexis oregmae fue encontrado en 10 sitios en 7 condados y con tasas de parasitismo en 4 sitios en 3 condados entre 0.7 a 3.3% en el 2001 y 2002, respectivamente. Las pruebas del laboratorio indicaron que las tasas altas de mortalidad fueron posibles si los afidos con parasitos recolectados en el campo fueron mantenidos en bolsas plasticas, entonces un ensayo molecular fue usado con lo que permitio la deteccion de inmaduros de L. oregmae dentro de los hospederos de afidos inmediatamente despues de la recoleccion. El ensayo molecular fue usado en el 2003 con individuos del afido pardo de los citricos y con otras especies de afidos recolectados sobre citricos, malezas y hortalizas cerca de los sitios donde los parasitoides fueron liberados anteriormente; inmaduros de L. oregmae fueron detectados en individuos del afido negro de los citricos, el afido del caupi, el afido spirea y el afido del melon, ademas del afido pardo de los citricos en 4 de los 8 condados muestreados, con la tasa del parasitismo entre 2.0 a12.9%, indicando que L. oregmae estaba estabecido y ampliamente distribuido. Las muestras tomadas en el Condado de Polk durante octobre del 2005 indicaron que L. oregmae ha persistido. La capacidad de L. oregmae para parasitar otras especies de afidos sobre citricos y otros afidos sobre otras plantas hospederas, incrementa la capacidad de L. oregmae para persistir cuando las poblaciones del afido pardo de los citricos estan bajas. (author)« less
  • The fish fauna associated with two U.S. Navy research platforms, Stage I and Stage II, in the northeastern Gulf of Mexico off Panama City, Fla., was studied at irregular intervals from 1970 to 1974. Such platforms function as artificial reef habitats and support diverse and abundant fish populations not normally characteristic of the open sandy bottoms in the area. A total of 101 taxa (identified to family or species) was recorded at the two platforms; 61 species were observed at Stage I in water 32 m deep and 86 taxa at Stage II in water 18 km deep. The greatermore » number of species recorded at the shallower location may be more a result of the greater number of observations made there than of differences in the two habitats. The number of species present at the platforms varies considerably at different times of the day and year. Species numbers are greatest during the summer and fall, but many species begin to move offshore or southward as the water temperature drops, and only about 50 to 60 percent of those recorded at the platform remain in December. The number of species diminishes to about 16 percent in February at Stage II, then increases gradually with the rising water temperature in the spring. Major species occupying the platform habitats include fishes usually characteristic of pelagic, inshore (coastal or estuarine), and rocky reef environments. At the platforms, the pelagic species and most of the larger predators occupy various levels of the water column, either directly below or surrounding the structure, while most of the other species are associated either with the pilings and cross-members of the platform or with the bottom. For some species, the platform provides food and shelter; for others, it offers only shelter. Some species may be present only to feed on numerous fishes and other organisms concentrated there. Diel rhythms of activity are obvious for many fishes, with some species active only during the day, and others only at night.« less
  • Some species of invertebrate animals are known to be efficient accumulators of trace elements. Generally, metal accumulation by such organisms is based on efficient detoxification mechanisms, such as intracellular compartmentalization, or metal inactivation by binding to metallothioneins. Metal accumulators have often been used as accumulation indicators of environmental metal pollution. This means that, ideally, metal concentrations on the animal`s body reflect quantitatively or semiquantitatively environmental pollution levels. In reality, however, many factors, such as the animal`s weight and age, can disturb such quantitative relationships. These factors have, therefore, to be considered carefully before an invertebrate is utilized as accumulation indicatormore » for metal pollution. Apart from accumulation, many invertebrates exposed to elevated metal concentrations respond to this stress by metal-induced synthesis of metallothioneins. Additionally, metallothionein in metal-loaded organisms can be present in different isoforms that are specifically synthesized in response to different metals. These facts make metallothionein a potential biomarker for metal stress in invertebrates. One possibility may be to assess parameters of metallothionein synthesis at the molecular or biochemical level. Moreover, metallothionein isoform patterns could provide information on different isoforms synthesized in response to different metals or chemicals. In any case, however, care must be taken to consider intrinsic physiological parameters, such as nutritional or developmental factors, which could also interfere with metallothionein synthesis. 15 refs., 2 figs.« less