PURPOSE: This technical note describes an aquarium study conducted to determine the efficacy of d... more PURPOSE: This technical note describes an aquarium study conducted to determine the efficacy of dried Mycoleptodiscus terrestris (Gerd.) Ostazeski against fluridone-susceptible and fluridoneresistant hydrilla biotypes. INTRODUCTION: Hydrilla verticillata (L.f.) Royle, a member of the Hydrocharitaceae, was introduced into Florida in the 1950’s (Schmitz et al. 1991). The introduction was the dioecious biotype with only gynoecious plants making up the original infestation. Today hydrilla has invaded at least 21 states either as dioecious or monoecious biotypes or both (Richardson 2008). Called “the perfect aquatic weed ” by Langeland (1996), the plant has several characteristics that make it an
PURPOSE: The purpose of this study was to determine the status of available documentation of the ... more PURPOSE: The purpose of this study was to determine the status of available documentation of the physiological ecology of several invasive aquatic species in relation to the ability to predict which sites will be susceptible to invasion. INTRODUCTION: As of 2001, it was estimated that approximately 50,000 nonindigenous species had been introduced into the United States (Pimentel et al. 2000). Some are beneficial, including food crops (e.g. corn, wheat), livestock (e.g. cattle, sheep), landscape enhancement (e.g. crape myrtles, boxwoods), or biological pest controls (e.g. host-specific biological control insects and pathogens). Others, however, have caused major economic losses and harmful impacts to the envi-ronment. Over the past 40 years, introductions have increased because of human population growth and mobility and increased trade among nations (Pimentel et al. 2000). Fundamental to establishment success for any invasive species is a source of food and a place to live and repro...
This study summarizes how a relatively simple model can be used to predict invasion potential by ... more This study summarizes how a relatively simple model can be used to predict invasion potential by an aquatic nuisance species. The spread and subsequent unlikely eradication of alien species from recently invaded ecosystems reinforces the need for predictive tools to help management personnel evaluate associated detrimental impacts. It is estimated that in most countries 102-104 nonindigenous species have been documented, and numbers should increase with expanding global trade and travel (Lodge 1993). Although only a small percent (usually < 10 percent) are invasive (Williamson and Fitter 1996), some have enormous economic and ecological impacts (Office of Technology Assessments (OTA) 1993; Ricciardi and Rasmussen 1998). For these reasons a need exists to determine which species will be introduced and which will cause impacts in order to allocate resources for prevention, detection, management, and control efforts (Grosholz and Ruiz 1996; Ricciardi and Rasmussen 1998; Colnar and L...
This technical note describes the results of multiple growth chamber studies conducted to evaluat... more This technical note describes the results of multiple growth chamber studies conducted to evaluate the effectiveness of three ALS-inhibiting herbicides (penoxsulam, imazamox, and bispyribac-sodium) and a fungal pathogen applied alone and in combination with one another, as a potential method for controlling the nuisance submersed plant, hydrilla (Hydrilla verticillata (L.f.) Royle).
PURPOSE: This technical note describes laboratory investigations conducted to evaluate the effect... more PURPOSE: This technical note describes laboratory investigations conducted to evaluate the effectiveness of the herbicide fluridone (1-methyl-3-phenyl-5(3-(trifluoromethyl)phenyl)-4(1H)- pyridinone) and the fungal pathogen Mt (Mycoleptodiscus terrestris (Gerd.) Ostazeski), applied alone and in combination with one another, against Eurasian watermilfoil (Myriophyllum spicatum L.). Results of this research will demonstrate the potential for integrating chemical and biological control tactics to improve the long-term
PURPOSE: This technical note describes the results of a laboratory investigation conducted to eva... more PURPOSE: This technical note describes the results of a laboratory investigation conducted to evaluate the effectiveness of the herbicide diquat (6,7-dihydrodipyrido(1,2-a:2',1'-c)pyrazinediium), and the fungal pathogen Mycoleptodiscus terrestris (Gerd.) Ostazeski, applied alone and in combina- tion with one another, as an integrated weed management strategy against the nuisance aquatic plant, hydrilla (Hydrilla verticillata (L.f.) Royle). BACKGROUND: Integrated weed management (IWM) can
ABSTRACT Growth chamber studies were conducted using 55-L aquariums to evaluate the efficacy of t... more ABSTRACT Growth chamber studies were conducted using 55-L aquariums to evaluate the efficacy of the herbicide triclopyr and the fungal pathogen Mycoleptodiscus terrestris, applied alone and in combination against Eurasian watermilfoil. Treatments included 0.15, 0.40, and 1.50 mg acid equivalent (ae)/L triclopyr, 0.08, 0.16, and 0.32 ml/L M. terrestris, combinations of both agents at all rates, and an untreated control. Plants were exposed to all treatments for a 24-h contact time and plant biomass (shoot and roots) was recorded 6 wk after application. For both triclopyr and M. terrestris applied alone, plant control increased with treatment concentration. Compared with untreated plants, 1.50 mg/L triclopyr and 0.32 ml/L M. terrestris reduced Eurasian watermilfoil by 100 and 91%, respectively. Lower doses of herbicide or pathogen were less effective and plant recovery was observed from surviving plant tissues (stems and root crowns). Although M. terrestris at 0.08 ml/L did not significantly reduce shoot or root biomass and 0.15 mg/L triclopyr provided only 53% control of plants, combining both agents at these rates reduced Eurasian watermilfoil by 90%. Results demonstrated that integrating low doses of triclopyr with an indigenous pathogen, M. terrestris, can improve control of Eurasian watermilfoil. Lower use rates of triclopyr would minimize impacts to sensitive nontarget vegetation, reduce application costs, and may minimize impacts of label-imposed use restrictions. Nomenclature: Triclopyr; Eurasian watermilfoil, Myriophyllum spicatum L. MYPSP; Mycoleptodiscus terrestris (Gerd.) Ostazeski
Page 1. 19990601 095 Aquatic Plant Control Technical Note IC-01 September 1998 Integrated Flurido... more Page 1. 19990601 095 Aquatic Plant Control Technical Note IC-01 September 1998 Integrated Fluridone-Fungal Pathogen Treatment of Four Submersed Plants PURPOSE: This technical note describes an outdoor mesocosm ...
We report progressive necrotizing fungal cellulitis and myositis in the leg of a patient with gli... more We report progressive necrotizing fungal cellulitis and myositis in the leg of a patient with glioblastoma multiforme treated with temozolomide and corticosteroids. While the morphologic appearance of the isolate and its ability to grow at temperatures greater than 32°C were suggestive of Mycoleptodiscus indicus, some of the conidia were atypical for this species in that they had single septa and occasional lateral appendages. Furthermore, the isolate was different from M. indicus based on the sequencing analysis of two rDNA regions. This is the first case of Mycoleptodiscus invasive fungal disease in which the causative agent could not be resolved at the species level because of inconsistencies between morphological and molecular data.
The submersed macrophyte, Hydrilla verticillata, was grown using different nutritional regimes un... more The submersed macrophyte, Hydrilla verticillata, was grown using different nutritional regimes under greenhouse conditions to obtain plants that were significantly different in percent nitrogen-free extract, crude fiber, ether-extractable compounds, crude protein, and ash in shoot tissue. Shoots were then challenged by the biological control fungal pathogen, Mycoleptodiscus terrestris, to determine the effects of plant nutritional status on disease severity, growth, and reproduction. Fourteen days post-inoculation, shoots from plants grown in high-fertility sediment had significantly greater disease severity ratings than shoots from plants grown in low-fertility sediment. The nutritional status of the plants also impacted asexual reproduction of the pathogen by thin-walled conidia and melanized survival structures called microsclerotia. At 14 days post-inoculation, significantly higher numbers of conidia were produced in flasks containing hydrilla plants grown in high-fertility sediment. In contrast, microsclerotia increased almost fourfold in leaf tissues of hydrilla grown in low-fertility sediment. It appears from these studies that the nutritional condition of target plants cannot be excluded as an important factor in efficacy of pathogens used as biological control agents. The nutritional status of the host tissues influences M. terrestris ingress into host tissues, vegetative growth, production of secondary inoculum in the form of disseminative spores or conidia, and production of survival structures, the microsclerotia.
Mycoleptodiscus terrestris has potential as an inundative biological control agent for the manage... more Mycoleptodiscus terrestris has potential as an inundative biological control agent for the management of hydrilla, one of the world's worst aquatic weeds. Essential to producing a marketable bioherbicidal product was the development of liquid culture procedures that would yield propagules that maintained biocontrol eYcacy. Since M. terrestris did not produce conidia in liquid culture, various nutritional conditions were evaluated as a means to produce high concentrations of stable fungal propagules such as microsclerotia. Evaluations of propagule formation and biomass yield were carried out in liquid culture media containing a basal salts solution amended with corn steep liquor powder or cottonseed meal combined with 4% or 6% glucose. Hyphal aggregation was observed by day 2, and by day 8 abundant melanized microsclerotia were present in the broth cultures. When applied as a liquid inoculum to hydrilla at rates of 0.1 and 0.2 ml/l, the microsclerotial matrix was capable of signiWcantly reducing hydrilla shoot biomass by as much as 99%. Air-dried microsclerotia were capable of hyphal germination in 24 h and sporogenic germination in 72 h. These capabilities have signiWcance for the use of microsclerotia of M. terrestris as the preferred inoculum for biocontrol purposes. Hyphae germinating from microsclerotia on hydrilla plant surfaces can establish initial infection sites followed several days later by secondary infections resulting from the development and release of spores from the surface of the microsclerotia. The capability of microsclerotia of M. terrestris to remain stable as a dry preparation and to germinate both hyphally and sporogenically upon rehydration enhances the potential of this fungus for use as a nonchemical, biological control agent for hydrilla.
The impact of growth temperature was evaluated for the fungal plant pathogen Mycoleptodiscus terr... more The impact of growth temperature was evaluated for the fungal plant pathogen Mycoleptodiscus terrestris over a range of temperatures (20Á368C). The effect of temperature on biomass accumulation, colony forming units (cfu), and microsclerotia production was determined. Culture temperatures of 24Á308C produced significantly higher biomass accumulations and 20Á248C resulted in a significantly higher cfu. The growth of M. terrestris was greatly reduced at temperatures above 308C and was absent at 368C. The highest microsclerotia concentrations were produced over a wide range of temperatures (20Á308C). These data suggest that a growth temperature of 248C would optimize the parameters evaluated in this study. In addition to growth parameters, we also evaluated the desiccation tolerance and storage stability of air-dried microsclerotial preparations from these cultures during storage at 48C. During 5 months storage, there was no significant difference in viability for air-dried microsclerotial preparations from cultures grown at 20Á308C (!72% hyphal germination) or in conidia production (sporogenic germination) for air-dried preparations from cultures grown at 20Á328C. When the effect of temperature on germination by air-dried microsclerotial preparations was evaluated, data showed that temperatures of 22Á308C were optimal for hyphal and sporogenic germination. Air-dried microsclerotial preparations did not germinate hyphally at 368C or sporogenically at 20, 32, 34, or 368C. These data show that temperature does impact the growth and germination of M. terrestris and suggest that water temperature may be a critical environmental consideration for the application of air-dried M. terrestris preparations for use in controlling hydrilla.
During a survey of submersed aquatic macrophytes and their associated fungi from lakes and waterw... more During a survey of submersed aquatic macrophytes and their associated fungi from lakes and waterways in New Zealand’s North Island, an isolate of Mycoleptodiscus terrestris (Gerd.) Ostaz. was confirmed on the basis of colony characteristics, sporodochia, and conidial morphology. This is a new record of M. terrestris in New Zealand and a new host species, the introduced aquatic macrophyte, Ceratophyllum
PURPOSE: This technical note describes an aquarium study conducted to determine the efficacy of d... more PURPOSE: This technical note describes an aquarium study conducted to determine the efficacy of dried Mycoleptodiscus terrestris (Gerd.) Ostazeski against fluridone-susceptible and fluridoneresistant hydrilla biotypes. INTRODUCTION: Hydrilla verticillata (L.f.) Royle, a member of the Hydrocharitaceae, was introduced into Florida in the 1950’s (Schmitz et al. 1991). The introduction was the dioecious biotype with only gynoecious plants making up the original infestation. Today hydrilla has invaded at least 21 states either as dioecious or monoecious biotypes or both (Richardson 2008). Called “the perfect aquatic weed ” by Langeland (1996), the plant has several characteristics that make it an
PURPOSE: The purpose of this study was to determine the status of available documentation of the ... more PURPOSE: The purpose of this study was to determine the status of available documentation of the physiological ecology of several invasive aquatic species in relation to the ability to predict which sites will be susceptible to invasion. INTRODUCTION: As of 2001, it was estimated that approximately 50,000 nonindigenous species had been introduced into the United States (Pimentel et al. 2000). Some are beneficial, including food crops (e.g. corn, wheat), livestock (e.g. cattle, sheep), landscape enhancement (e.g. crape myrtles, boxwoods), or biological pest controls (e.g. host-specific biological control insects and pathogens). Others, however, have caused major economic losses and harmful impacts to the envi-ronment. Over the past 40 years, introductions have increased because of human population growth and mobility and increased trade among nations (Pimentel et al. 2000). Fundamental to establishment success for any invasive species is a source of food and a place to live and repro...
This study summarizes how a relatively simple model can be used to predict invasion potential by ... more This study summarizes how a relatively simple model can be used to predict invasion potential by an aquatic nuisance species. The spread and subsequent unlikely eradication of alien species from recently invaded ecosystems reinforces the need for predictive tools to help management personnel evaluate associated detrimental impacts. It is estimated that in most countries 102-104 nonindigenous species have been documented, and numbers should increase with expanding global trade and travel (Lodge 1993). Although only a small percent (usually < 10 percent) are invasive (Williamson and Fitter 1996), some have enormous economic and ecological impacts (Office of Technology Assessments (OTA) 1993; Ricciardi and Rasmussen 1998). For these reasons a need exists to determine which species will be introduced and which will cause impacts in order to allocate resources for prevention, detection, management, and control efforts (Grosholz and Ruiz 1996; Ricciardi and Rasmussen 1998; Colnar and L...
This technical note describes the results of multiple growth chamber studies conducted to evaluat... more This technical note describes the results of multiple growth chamber studies conducted to evaluate the effectiveness of three ALS-inhibiting herbicides (penoxsulam, imazamox, and bispyribac-sodium) and a fungal pathogen applied alone and in combination with one another, as a potential method for controlling the nuisance submersed plant, hydrilla (Hydrilla verticillata (L.f.) Royle).
PURPOSE: This technical note describes laboratory investigations conducted to evaluate the effect... more PURPOSE: This technical note describes laboratory investigations conducted to evaluate the effectiveness of the herbicide fluridone (1-methyl-3-phenyl-5(3-(trifluoromethyl)phenyl)-4(1H)- pyridinone) and the fungal pathogen Mt (Mycoleptodiscus terrestris (Gerd.) Ostazeski), applied alone and in combination with one another, against Eurasian watermilfoil (Myriophyllum spicatum L.). Results of this research will demonstrate the potential for integrating chemical and biological control tactics to improve the long-term
PURPOSE: This technical note describes the results of a laboratory investigation conducted to eva... more PURPOSE: This technical note describes the results of a laboratory investigation conducted to evaluate the effectiveness of the herbicide diquat (6,7-dihydrodipyrido(1,2-a:2',1'-c)pyrazinediium), and the fungal pathogen Mycoleptodiscus terrestris (Gerd.) Ostazeski, applied alone and in combina- tion with one another, as an integrated weed management strategy against the nuisance aquatic plant, hydrilla (Hydrilla verticillata (L.f.) Royle). BACKGROUND: Integrated weed management (IWM) can
ABSTRACT Growth chamber studies were conducted using 55-L aquariums to evaluate the efficacy of t... more ABSTRACT Growth chamber studies were conducted using 55-L aquariums to evaluate the efficacy of the herbicide triclopyr and the fungal pathogen Mycoleptodiscus terrestris, applied alone and in combination against Eurasian watermilfoil. Treatments included 0.15, 0.40, and 1.50 mg acid equivalent (ae)/L triclopyr, 0.08, 0.16, and 0.32 ml/L M. terrestris, combinations of both agents at all rates, and an untreated control. Plants were exposed to all treatments for a 24-h contact time and plant biomass (shoot and roots) was recorded 6 wk after application. For both triclopyr and M. terrestris applied alone, plant control increased with treatment concentration. Compared with untreated plants, 1.50 mg/L triclopyr and 0.32 ml/L M. terrestris reduced Eurasian watermilfoil by 100 and 91%, respectively. Lower doses of herbicide or pathogen were less effective and plant recovery was observed from surviving plant tissues (stems and root crowns). Although M. terrestris at 0.08 ml/L did not significantly reduce shoot or root biomass and 0.15 mg/L triclopyr provided only 53% control of plants, combining both agents at these rates reduced Eurasian watermilfoil by 90%. Results demonstrated that integrating low doses of triclopyr with an indigenous pathogen, M. terrestris, can improve control of Eurasian watermilfoil. Lower use rates of triclopyr would minimize impacts to sensitive nontarget vegetation, reduce application costs, and may minimize impacts of label-imposed use restrictions. Nomenclature: Triclopyr; Eurasian watermilfoil, Myriophyllum spicatum L. MYPSP; Mycoleptodiscus terrestris (Gerd.) Ostazeski
Page 1. 19990601 095 Aquatic Plant Control Technical Note IC-01 September 1998 Integrated Flurido... more Page 1. 19990601 095 Aquatic Plant Control Technical Note IC-01 September 1998 Integrated Fluridone-Fungal Pathogen Treatment of Four Submersed Plants PURPOSE: This technical note describes an outdoor mesocosm ...
We report progressive necrotizing fungal cellulitis and myositis in the leg of a patient with gli... more We report progressive necrotizing fungal cellulitis and myositis in the leg of a patient with glioblastoma multiforme treated with temozolomide and corticosteroids. While the morphologic appearance of the isolate and its ability to grow at temperatures greater than 32°C were suggestive of Mycoleptodiscus indicus, some of the conidia were atypical for this species in that they had single septa and occasional lateral appendages. Furthermore, the isolate was different from M. indicus based on the sequencing analysis of two rDNA regions. This is the first case of Mycoleptodiscus invasive fungal disease in which the causative agent could not be resolved at the species level because of inconsistencies between morphological and molecular data.
The submersed macrophyte, Hydrilla verticillata, was grown using different nutritional regimes un... more The submersed macrophyte, Hydrilla verticillata, was grown using different nutritional regimes under greenhouse conditions to obtain plants that were significantly different in percent nitrogen-free extract, crude fiber, ether-extractable compounds, crude protein, and ash in shoot tissue. Shoots were then challenged by the biological control fungal pathogen, Mycoleptodiscus terrestris, to determine the effects of plant nutritional status on disease severity, growth, and reproduction. Fourteen days post-inoculation, shoots from plants grown in high-fertility sediment had significantly greater disease severity ratings than shoots from plants grown in low-fertility sediment. The nutritional status of the plants also impacted asexual reproduction of the pathogen by thin-walled conidia and melanized survival structures called microsclerotia. At 14 days post-inoculation, significantly higher numbers of conidia were produced in flasks containing hydrilla plants grown in high-fertility sediment. In contrast, microsclerotia increased almost fourfold in leaf tissues of hydrilla grown in low-fertility sediment. It appears from these studies that the nutritional condition of target plants cannot be excluded as an important factor in efficacy of pathogens used as biological control agents. The nutritional status of the host tissues influences M. terrestris ingress into host tissues, vegetative growth, production of secondary inoculum in the form of disseminative spores or conidia, and production of survival structures, the microsclerotia.
Mycoleptodiscus terrestris has potential as an inundative biological control agent for the manage... more Mycoleptodiscus terrestris has potential as an inundative biological control agent for the management of hydrilla, one of the world's worst aquatic weeds. Essential to producing a marketable bioherbicidal product was the development of liquid culture procedures that would yield propagules that maintained biocontrol eYcacy. Since M. terrestris did not produce conidia in liquid culture, various nutritional conditions were evaluated as a means to produce high concentrations of stable fungal propagules such as microsclerotia. Evaluations of propagule formation and biomass yield were carried out in liquid culture media containing a basal salts solution amended with corn steep liquor powder or cottonseed meal combined with 4% or 6% glucose. Hyphal aggregation was observed by day 2, and by day 8 abundant melanized microsclerotia were present in the broth cultures. When applied as a liquid inoculum to hydrilla at rates of 0.1 and 0.2 ml/l, the microsclerotial matrix was capable of signiWcantly reducing hydrilla shoot biomass by as much as 99%. Air-dried microsclerotia were capable of hyphal germination in 24 h and sporogenic germination in 72 h. These capabilities have signiWcance for the use of microsclerotia of M. terrestris as the preferred inoculum for biocontrol purposes. Hyphae germinating from microsclerotia on hydrilla plant surfaces can establish initial infection sites followed several days later by secondary infections resulting from the development and release of spores from the surface of the microsclerotia. The capability of microsclerotia of M. terrestris to remain stable as a dry preparation and to germinate both hyphally and sporogenically upon rehydration enhances the potential of this fungus for use as a nonchemical, biological control agent for hydrilla.
The impact of growth temperature was evaluated for the fungal plant pathogen Mycoleptodiscus terr... more The impact of growth temperature was evaluated for the fungal plant pathogen Mycoleptodiscus terrestris over a range of temperatures (20Á368C). The effect of temperature on biomass accumulation, colony forming units (cfu), and microsclerotia production was determined. Culture temperatures of 24Á308C produced significantly higher biomass accumulations and 20Á248C resulted in a significantly higher cfu. The growth of M. terrestris was greatly reduced at temperatures above 308C and was absent at 368C. The highest microsclerotia concentrations were produced over a wide range of temperatures (20Á308C). These data suggest that a growth temperature of 248C would optimize the parameters evaluated in this study. In addition to growth parameters, we also evaluated the desiccation tolerance and storage stability of air-dried microsclerotial preparations from these cultures during storage at 48C. During 5 months storage, there was no significant difference in viability for air-dried microsclerotial preparations from cultures grown at 20Á308C (!72% hyphal germination) or in conidia production (sporogenic germination) for air-dried preparations from cultures grown at 20Á328C. When the effect of temperature on germination by air-dried microsclerotial preparations was evaluated, data showed that temperatures of 22Á308C were optimal for hyphal and sporogenic germination. Air-dried microsclerotial preparations did not germinate hyphally at 368C or sporogenically at 20, 32, 34, or 368C. These data show that temperature does impact the growth and germination of M. terrestris and suggest that water temperature may be a critical environmental consideration for the application of air-dried M. terrestris preparations for use in controlling hydrilla.
During a survey of submersed aquatic macrophytes and their associated fungi from lakes and waterw... more During a survey of submersed aquatic macrophytes and their associated fungi from lakes and waterways in New Zealand’s North Island, an isolate of Mycoleptodiscus terrestris (Gerd.) Ostaz. was confirmed on the basis of colony characteristics, sporodochia, and conidial morphology. This is a new record of M. terrestris in New Zealand and a new host species, the introduced aquatic macrophyte, Ceratophyllum
Uploads
Papers by Judy Shearer