Follow the yellow flag road : advancing the biological control of a global wetland invader, and a case study on ecosystem recovery
- Authors: Minuti, Gianmarco
- Date: 2025-04-03
- Subjects: Aquatic plants , Invasive plants Biological control , Iris pseudacorus , Azolla filiculoides , Aphthona nonstriata , Host specificity
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/479908 , vital:78378 , DOI 10.21504/10962/479908
- Description: Global change is accelerating habitat degradation and extinction rates, disproportionately affecting freshwater ecosystems. Biological invasions, a core component of global change, have been recognized as a major driver of this phenomenon. Invasive alien aquatic plants (IAAPs) are a prime example, disrupting ecological dynamics and hindering the economic and social activities that depend upon freshwater ecosystems. The best approach to managing IAAPs is preventing their introduction and taking swift action when infestations are detected. Unfortunately, most IAAPs are only recognized after they have spread, making eradication difficult and requiring expensive, ongoing management through manual, mechanical, or chemical means, which become less effective as infestations grow. In this regard, a sustainable alternative against IAAPs is provided by classical biological control. This method lays on the assumption that invasive species have been introduced in an environment which is free from their natural enemies, and that such release allowed them to redirect their resources towards growth and reproduction. Accordingly, weed biocontrol involves introducing one such enemy - a so-called biocontrol agent - to regulate the population of the plant, ideally reducing its density below a critical threshold, minimizing its impacts. Biocontrol programs must follow stringent protocols in order to a) ensure the selection of the most appropriate agents; b) guarantee their establishment and effectiveness in controlling their target; c) minimize the risks involved with their release; and d) monitor their impacts after they have been released. This thesis is composed of two parts, focusing on pre-release studies (Part I, Chapters 1-4) and post-release evaluations (Part II, Chapter 5), respectively. Part I explores the biological control of Iris pseudacorus L. (Iridaceae) – yellow flag – a Eurasian plant that has invaded temperate wetlands worldwide. The first step consisted of conducting field surveys across the native range of the weed, which led to the selection of three candidate biocontrol agents. As a second step, bioclimatic niche modelling was used to forecast the current and future suitability of the weed and its prospective agents. These models helped to identify areas most at risk of invasion and predict how climate change might affect biocontrol efficacy, showing differing impacts in the Northern and Southern Hemispheres. Further, a scoring system was developed to prioritize non-target plants for host-specificity testing, focusing on species within the family Iridaceae. Most taxa prioritized are native to the Americas, South Africa and eastern Asia, highlighting the importance of collaboration across regions when dealing with global invaders with complex phylogeographic distributions. Finally, a germination study confirmed that I. pseudacorus seeds from Argentina germinate more than Belgian seeds, especially in absence of cold stratification, suggesting increased performances of invasive populations and an adaptation to warmer temperatures. Nonetheless, impact assessments conducted on one of the three biocontrol agents demonstrated that it could cause juvenile mortality, suggesting it may effectively reduce seedling recruitment, though further research on agents targeting reproductive structures is recommended. Part II of the thesis addresses an often understudied aspect of post-release evaluations: ecosystem recovery following biological control. To do so, a case study is presented, investigating the biological control of water fern, Azolla filiculoides Lamb. (Salviniaceae), in Belgium. The results of this study are used to discuss the shortcomings of different experimental designs, the lack of baseline data in invasion ecology, and the intricacies of defining and quantifying ecosystem recovery in light of legacy effects and context-dependency. , Wereldwijde verandering versnelt de degradatie van habitats en de uitstervingscijfers, met een onevenredige impact op zoetwaterecosystemen. Biologische invasies, een kernonderdeel van klimaatverandering, worden erkend als een belangrijke drijvende kracht achter dit fenomeen. Invasieve uitheemse waterplanten (IAAPs) zijn een duidelijk voorbeeld, omdat ze ecologische dynamiek verstoren en economische en sociale activiteiten belemmeren die afhankelijk zijn van zoetwaterecosystemen. De beste aanpak voor het beheer van IAAPs is het voorkomen van hun introductie en het nemen van snelle maatregelen bij het detecteren van besmettingen. Helaas worden de meeste IAAPs pas herkend nadat ze zich hebben verspreid, wat uitroeiing moeilijk maakt en dure, voortdurende beheersing vereist door handmatige, mechanische of chemische middelen, die minder effectief worden naarmate besmettingen toenemen. In dit opzicht biedt klassieke biologische bestrijding een duurzaam alternatief tegen IAAPs. Deze methode berust op de veronderstelling dat invasieve soorten zijn geïntroduceerd in een omgeving die vrij is van hun natuurlijke vijanden, waardoor ze hun middelen konden richten op groei en reproductie. Bijgevolg omvat onkruidbestrijding het introduceren van een dergelijke vijand - een zogenaamde biocontrole-agent - om de populatie van de plant te reguleren, idealiter door de dichtheid ervan onder een kritische drempel te verlagen en zo de impact ervan te minimaliseren. Biocontroleprogramma's moeten strikte protocollen volgen om a) de selectie van de meest geschikte agens te waarborgen; b) hun vestiging en effectiviteit bij het beheersen van hun doel te garanderen; c) de risico's van hun vrijlating te minimaliseren; en d) hun impact na vrijlating te monitoren. Dit proefschrift bestaat uit twee delen, gericht op respectievelijk pre-release studies (Deel I, Hoofdstukken 1-4) en post-release evaluaties (Deel II, Hoofdstuk 5). Deel I onderzoekt de biologische bestrijding van Iris pseudacorus L. (Iridaceae) - gele lis - een Euraziatische plant die gematigde moeraslanden wereldwijd heeft gekoloniseerd. De eerste stap bestond uit het uitvoeren van veldonderzoeken in het inheemse verspreidingsgebied van het onkruid, wat leidde tot de selectie van drie kandidaat-biocontroleagenten. Als tweede stap werd bioklimatisch nis-modelleren gebruikt om de huidige en toekomstige geschiktheid van het onkruid en zijn potentiële agens te voorspellen. Deze modellen hielpen gebieden met het grootste risico op invasie te identificeren en voorspelden hoe klimaatverandering de effectiviteit van biocontrole zou kunnen beïnvloeden, met verschillende effecten op het noordelijk en zuidelijk halfrond. Daarnaast werd een scoresysteem ontwikkeld om niet-doelplanten te prioriteren voor host-specifieke tests, met de nadruk op soorten binnen de familie Iridaceae. De prioritaire taxa zijn inheems in Amerika, Zuid-Afrika en Oost-Azië, wat het belang van samenwerking tussen regio’s onderstreept bij het omgaan met mondiale invasieve soorten met complexe fylogeografische verspreiding. Ten slotte bevestigde een kiemingsstudie dat I. pseudacorus zaden uit Argentinië meer kiemen dan Belgische zaden, vooral bij afwezigheid van koude stratificatie, wat wijst op verhoogde prestaties van invasieve populaties en aanpassing aan warmere temperaturen. Nochtans toonden effectbeoordelingen van een van de drie biocontroleagens aan dat deze de mortaliteit van juvenielen kon veroorzaken, wat suggereert dat het effectief kan zijn bij het verminderen van de zaailingrekrutering. Toch wordt verder onderzoek naar agenten die zich richten op reproductieve structuren aanbevolen. Deel II van het proefschrift behandelt een vaak onderbelicht aspect van post-release evaluaties: ecosysteemherstel na biologische bestrijding. Om dit te realiseren wordt een casestudy aangeboden over de biologische bestrijding van watervaren, Azolla filiculoides Lamb. (Salviniaceae), in België. De resultaten van deze studie worden gebruikt voor de bespreking van de tekortkomingen van verschillende experimentele ontwerpen, het gebrek aan basisgegevens in invasie-ecologie en de complexiteit van het definiëren en kwantificeren van ecosysteemherstel in het licht van nalatenschapseffecten en contextafhankelijkheid. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2025
- Full Text:
- Date Issued: 2025-04-03
- Authors: Minuti, Gianmarco
- Date: 2025-04-03
- Subjects: Aquatic plants , Invasive plants Biological control , Iris pseudacorus , Azolla filiculoides , Aphthona nonstriata , Host specificity
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/479908 , vital:78378 , DOI 10.21504/10962/479908
- Description: Global change is accelerating habitat degradation and extinction rates, disproportionately affecting freshwater ecosystems. Biological invasions, a core component of global change, have been recognized as a major driver of this phenomenon. Invasive alien aquatic plants (IAAPs) are a prime example, disrupting ecological dynamics and hindering the economic and social activities that depend upon freshwater ecosystems. The best approach to managing IAAPs is preventing their introduction and taking swift action when infestations are detected. Unfortunately, most IAAPs are only recognized after they have spread, making eradication difficult and requiring expensive, ongoing management through manual, mechanical, or chemical means, which become less effective as infestations grow. In this regard, a sustainable alternative against IAAPs is provided by classical biological control. This method lays on the assumption that invasive species have been introduced in an environment which is free from their natural enemies, and that such release allowed them to redirect their resources towards growth and reproduction. Accordingly, weed biocontrol involves introducing one such enemy - a so-called biocontrol agent - to regulate the population of the plant, ideally reducing its density below a critical threshold, minimizing its impacts. Biocontrol programs must follow stringent protocols in order to a) ensure the selection of the most appropriate agents; b) guarantee their establishment and effectiveness in controlling their target; c) minimize the risks involved with their release; and d) monitor their impacts after they have been released. This thesis is composed of two parts, focusing on pre-release studies (Part I, Chapters 1-4) and post-release evaluations (Part II, Chapter 5), respectively. Part I explores the biological control of Iris pseudacorus L. (Iridaceae) – yellow flag – a Eurasian plant that has invaded temperate wetlands worldwide. The first step consisted of conducting field surveys across the native range of the weed, which led to the selection of three candidate biocontrol agents. As a second step, bioclimatic niche modelling was used to forecast the current and future suitability of the weed and its prospective agents. These models helped to identify areas most at risk of invasion and predict how climate change might affect biocontrol efficacy, showing differing impacts in the Northern and Southern Hemispheres. Further, a scoring system was developed to prioritize non-target plants for host-specificity testing, focusing on species within the family Iridaceae. Most taxa prioritized are native to the Americas, South Africa and eastern Asia, highlighting the importance of collaboration across regions when dealing with global invaders with complex phylogeographic distributions. Finally, a germination study confirmed that I. pseudacorus seeds from Argentina germinate more than Belgian seeds, especially in absence of cold stratification, suggesting increased performances of invasive populations and an adaptation to warmer temperatures. Nonetheless, impact assessments conducted on one of the three biocontrol agents demonstrated that it could cause juvenile mortality, suggesting it may effectively reduce seedling recruitment, though further research on agents targeting reproductive structures is recommended. Part II of the thesis addresses an often understudied aspect of post-release evaluations: ecosystem recovery following biological control. To do so, a case study is presented, investigating the biological control of water fern, Azolla filiculoides Lamb. (Salviniaceae), in Belgium. The results of this study are used to discuss the shortcomings of different experimental designs, the lack of baseline data in invasion ecology, and the intricacies of defining and quantifying ecosystem recovery in light of legacy effects and context-dependency. , Wereldwijde verandering versnelt de degradatie van habitats en de uitstervingscijfers, met een onevenredige impact op zoetwaterecosystemen. Biologische invasies, een kernonderdeel van klimaatverandering, worden erkend als een belangrijke drijvende kracht achter dit fenomeen. Invasieve uitheemse waterplanten (IAAPs) zijn een duidelijk voorbeeld, omdat ze ecologische dynamiek verstoren en economische en sociale activiteiten belemmeren die afhankelijk zijn van zoetwaterecosystemen. De beste aanpak voor het beheer van IAAPs is het voorkomen van hun introductie en het nemen van snelle maatregelen bij het detecteren van besmettingen. Helaas worden de meeste IAAPs pas herkend nadat ze zich hebben verspreid, wat uitroeiing moeilijk maakt en dure, voortdurende beheersing vereist door handmatige, mechanische of chemische middelen, die minder effectief worden naarmate besmettingen toenemen. In dit opzicht biedt klassieke biologische bestrijding een duurzaam alternatief tegen IAAPs. Deze methode berust op de veronderstelling dat invasieve soorten zijn geïntroduceerd in een omgeving die vrij is van hun natuurlijke vijanden, waardoor ze hun middelen konden richten op groei en reproductie. Bijgevolg omvat onkruidbestrijding het introduceren van een dergelijke vijand - een zogenaamde biocontrole-agent - om de populatie van de plant te reguleren, idealiter door de dichtheid ervan onder een kritische drempel te verlagen en zo de impact ervan te minimaliseren. Biocontroleprogramma's moeten strikte protocollen volgen om a) de selectie van de meest geschikte agens te waarborgen; b) hun vestiging en effectiviteit bij het beheersen van hun doel te garanderen; c) de risico's van hun vrijlating te minimaliseren; en d) hun impact na vrijlating te monitoren. Dit proefschrift bestaat uit twee delen, gericht op respectievelijk pre-release studies (Deel I, Hoofdstukken 1-4) en post-release evaluaties (Deel II, Hoofdstuk 5). Deel I onderzoekt de biologische bestrijding van Iris pseudacorus L. (Iridaceae) - gele lis - een Euraziatische plant die gematigde moeraslanden wereldwijd heeft gekoloniseerd. De eerste stap bestond uit het uitvoeren van veldonderzoeken in het inheemse verspreidingsgebied van het onkruid, wat leidde tot de selectie van drie kandidaat-biocontroleagenten. Als tweede stap werd bioklimatisch nis-modelleren gebruikt om de huidige en toekomstige geschiktheid van het onkruid en zijn potentiële agens te voorspellen. Deze modellen hielpen gebieden met het grootste risico op invasie te identificeren en voorspelden hoe klimaatverandering de effectiviteit van biocontrole zou kunnen beïnvloeden, met verschillende effecten op het noordelijk en zuidelijk halfrond. Daarnaast werd een scoresysteem ontwikkeld om niet-doelplanten te prioriteren voor host-specifieke tests, met de nadruk op soorten binnen de familie Iridaceae. De prioritaire taxa zijn inheems in Amerika, Zuid-Afrika en Oost-Azië, wat het belang van samenwerking tussen regio’s onderstreept bij het omgaan met mondiale invasieve soorten met complexe fylogeografische verspreiding. Ten slotte bevestigde een kiemingsstudie dat I. pseudacorus zaden uit Argentinië meer kiemen dan Belgische zaden, vooral bij afwezigheid van koude stratificatie, wat wijst op verhoogde prestaties van invasieve populaties en aanpassing aan warmere temperaturen. Nochtans toonden effectbeoordelingen van een van de drie biocontroleagens aan dat deze de mortaliteit van juvenielen kon veroorzaken, wat suggereert dat het effectief kan zijn bij het verminderen van de zaailingrekrutering. Toch wordt verder onderzoek naar agenten die zich richten op reproductieve structuren aanbevolen. Deel II van het proefschrift behandelt een vaak onderbelicht aspect van post-release evaluaties: ecosysteemherstel na biologische bestrijding. Om dit te realiseren wordt een casestudy aangeboden over de biologische bestrijding van watervaren, Azolla filiculoides Lamb. (Salviniaceae), in België. De resultaten van deze studie worden gebruikt voor de bespreking van de tekortkomingen van verschillende experimentele ontwerpen, het gebrek aan basisgegevens in invasie-ecologie en de complexiteit van het definiëren en kwantificeren van ecosysteemherstel in het licht van nalatenschapseffecten en contextafhankelijkheid. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2025
- Full Text:
- Date Issued: 2025-04-03
Contrasting effects of climate change on the invasion risk and biocontrol potential of the invasive Iris pseudacorus L. between Northern and Southern Hemisphere
- Minuti, Gianmarco, Coetzee, Julie A, Stiers, Iris
- Authors: Minuti, Gianmarco , Coetzee, Julie A , Stiers, Iris
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423329 , vital:72048 , xlink:href="https://doi.org/10.1016/j.biocontrol.2023.105290"
- Description: Iris pseudacorus is both a prized ornamental and an invasive aquatic plant that tends to grow dense monospecific stands, displacing the local vegetation and altering the hydrology of freshwater ecosystems. Originally from Europe, this species has historically invaded North America, China and Japan, and more recently spread through Argentina, South Africa and Australasia, where it is now a target for biological control. Field surveys within its native range have led to the selection of three candidate biocontrol agents. Prioritizing the best candidates for different regions constitutes a critical step, which could save significant time and resources before further cost-intensive experimental studies are conducted. Climate change is seldom taken into consideration in the prioritization process. In this regard, climatic suitability can be used to model the potential distributions of weeds and their candidate agents, both in space and time, thus allowing to identify areas at risk of invasion and predict where agents will be able to establish long-term. Accordingly, the objectives of this work were (i) to predict I. pseudacorus invasions and range shifts in the context of climate change; (ii) to identify wetland areas most at risk of invasion under present and future climatic conditions; and (iii) to prioritize the best suite of candidate biocontrol agents for different invaded ranges, worldwide. To do so, we modelled the present and future (2040–2060) climatic suitability of I. pseudacorus and its candidate agents using the software MaxEnt. Our results highlight a clear distinction between predictions for the Northern and Southern Hemispheres. In North America and eastern Asia, the area climatically suitable for I. pseudacorus is expected to increase and shift northwards. As for its biocontrol agents, very low suitability is predicted across these regions, further decreasing under future climatic conditions. On the other hand, climatically suitable areas for the plant in South America, southern Africa and Australasia are predicted, on average, to reduce in response to climate change. A decrease in climatic suitability is also expected for its candidate biocontrol agents which, however, would still maintain a significant range overlap with their host. These results can be used to prioritize areas most at risk of invasion and identify which combination of candidates could potentially provide the best level of control across different invaded ranges.
- Full Text:
- Date Issued: 2023
- Authors: Minuti, Gianmarco , Coetzee, Julie A , Stiers, Iris
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423329 , vital:72048 , xlink:href="https://doi.org/10.1016/j.biocontrol.2023.105290"
- Description: Iris pseudacorus is both a prized ornamental and an invasive aquatic plant that tends to grow dense monospecific stands, displacing the local vegetation and altering the hydrology of freshwater ecosystems. Originally from Europe, this species has historically invaded North America, China and Japan, and more recently spread through Argentina, South Africa and Australasia, where it is now a target for biological control. Field surveys within its native range have led to the selection of three candidate biocontrol agents. Prioritizing the best candidates for different regions constitutes a critical step, which could save significant time and resources before further cost-intensive experimental studies are conducted. Climate change is seldom taken into consideration in the prioritization process. In this regard, climatic suitability can be used to model the potential distributions of weeds and their candidate agents, both in space and time, thus allowing to identify areas at risk of invasion and predict where agents will be able to establish long-term. Accordingly, the objectives of this work were (i) to predict I. pseudacorus invasions and range shifts in the context of climate change; (ii) to identify wetland areas most at risk of invasion under present and future climatic conditions; and (iii) to prioritize the best suite of candidate biocontrol agents for different invaded ranges, worldwide. To do so, we modelled the present and future (2040–2060) climatic suitability of I. pseudacorus and its candidate agents using the software MaxEnt. Our results highlight a clear distinction between predictions for the Northern and Southern Hemispheres. In North America and eastern Asia, the area climatically suitable for I. pseudacorus is expected to increase and shift northwards. As for its biocontrol agents, very low suitability is predicted across these regions, further decreasing under future climatic conditions. On the other hand, climatically suitable areas for the plant in South America, southern Africa and Australasia are predicted, on average, to reduce in response to climate change. A decrease in climatic suitability is also expected for its candidate biocontrol agents which, however, would still maintain a significant range overlap with their host. These results can be used to prioritize areas most at risk of invasion and identify which combination of candidates could potentially provide the best level of control across different invaded ranges.
- Full Text:
- Date Issued: 2023
Climatic suitability and compatibility of the invasive Iris pseudacorus L.(Iridaceae) in the Southern Hemisphere: Considerations for biocontrol
- Minuti, Gianmarco, Stiers, Iris, Coetzee, Julie A
- Authors: Minuti, Gianmarco , Stiers, Iris , Coetzee, Julie A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423293 , vital:72045 , xlink:href="https://doi.org/10.1016/j.biocontrol.2022.104886"
- Description: Iris pseudacorus L. (Iridaceae) is an emergent macrophyte native to Europe, North Africa and western Asia. Considered invasive in wetland habitats around the world, this species is now the target of a biocontrol programme in the Southern Hemisphere. Native range surveys of the weed led to the selection of the flea beetle, Aphthona nonstriata Goeze (Coleoptera: Chrysomelidae), as a candidate biocontrol agent. An important aspect to consider in weed biocontrol is the ability of an agent to establish and thrive in the environment where it is released. Climatic incompatibility between source and intended release sites can in fact limit the success of a biocontrol programme. In the current study, the potential climatic niche of I. pseudacorus and A. nonstriata in the Southern Hemisphere was analysed. The ecological niche modelling software MaxEnt was used to map the climatic suitability of both organisms across invaded regions in South America, southern Africa and Australasia. Furthermore, occurrence records from each invaded range were used independently to model the climatic compatibility of I. pseudacorus in Europe, in order to prioritize areas of the native range to explore during future surveys for potential biocontrol agents. The models identified areas at high risk of invasion by I. pseudacorus in northern Argentina, Uruguay, southern Brazil and central Chile, as well as numerous provinces of eastern South Africa, Lesotho, southern Australia and New Zealand. Accordingly, the highest climatic suitability for A. nonstriata was predicted across the humid temperate climates of north-east Argentina, Uruguay, southern Brazil, southern South Africa, south-east Australia and New Zealand. These results can eventually be used in future release plans to prioritize areas where establishment and survival of the agent is expected to be highest. At the same time, it may be useful to search the native range of the weed for biological control agents showing high climatic adaptation towards the intended release sites of each invaded range. In this regards, our climatic compatibility models identified high-priority areas across the Mediterranean regions of Italy and southern France, as well as the temperate regions of central and western Europe. Altogether, the current study provides useful new information to tackle the invasion and advance the biocontrol programme of I. pseudacorus in the Southern Hemisphere.
- Full Text:
- Date Issued: 2022
- Authors: Minuti, Gianmarco , Stiers, Iris , Coetzee, Julie A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423293 , vital:72045 , xlink:href="https://doi.org/10.1016/j.biocontrol.2022.104886"
- Description: Iris pseudacorus L. (Iridaceae) is an emergent macrophyte native to Europe, North Africa and western Asia. Considered invasive in wetland habitats around the world, this species is now the target of a biocontrol programme in the Southern Hemisphere. Native range surveys of the weed led to the selection of the flea beetle, Aphthona nonstriata Goeze (Coleoptera: Chrysomelidae), as a candidate biocontrol agent. An important aspect to consider in weed biocontrol is the ability of an agent to establish and thrive in the environment where it is released. Climatic incompatibility between source and intended release sites can in fact limit the success of a biocontrol programme. In the current study, the potential climatic niche of I. pseudacorus and A. nonstriata in the Southern Hemisphere was analysed. The ecological niche modelling software MaxEnt was used to map the climatic suitability of both organisms across invaded regions in South America, southern Africa and Australasia. Furthermore, occurrence records from each invaded range were used independently to model the climatic compatibility of I. pseudacorus in Europe, in order to prioritize areas of the native range to explore during future surveys for potential biocontrol agents. The models identified areas at high risk of invasion by I. pseudacorus in northern Argentina, Uruguay, southern Brazil and central Chile, as well as numerous provinces of eastern South Africa, Lesotho, southern Australia and New Zealand. Accordingly, the highest climatic suitability for A. nonstriata was predicted across the humid temperate climates of north-east Argentina, Uruguay, southern Brazil, southern South Africa, south-east Australia and New Zealand. These results can eventually be used in future release plans to prioritize areas where establishment and survival of the agent is expected to be highest. At the same time, it may be useful to search the native range of the weed for biological control agents showing high climatic adaptation towards the intended release sites of each invaded range. In this regards, our climatic compatibility models identified high-priority areas across the Mediterranean regions of Italy and southern France, as well as the temperate regions of central and western Europe. Altogether, the current study provides useful new information to tackle the invasion and advance the biocontrol programme of I. pseudacorus in the Southern Hemisphere.
- Full Text:
- Date Issued: 2022
Prospects for the biological control of Iris pseudacorus L(Iridaceae)
- Minuti, Gianmarco, Coetzee, Julie A, Ngxande-Koza, Samella W, Hill, Martin P, Stiers, Iris
- Authors: Minuti, Gianmarco , Coetzee, Julie A , Ngxande-Koza, Samella W , Hill, Martin P , Stiers, Iris
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417776 , vital:71485 , xlink:href="https://doi.org/10.1080/09583157.2020.1853050"
- Description: Native to Europe, North Africa and western Asia, Iris pseudacorus L. (Iridaceae) has invaded natural and human-modified wetlands worldwide. This species is considered a noxious weed in several countries including Argentina, South Africa and New Zealand. Its broad ecological tolerance, high resilience and reproductive potential make current mechanical and chemical control measures cost-ineffective, and biological control is considered a suitable alternative. In order to prioritise candidate biocontrol agents, a list of organisms reported to attack the plant within its native range has been assembled, and information about their host-range and damaging potential gathered from the literature. Furthermore, surveys for natural enemies of the plant were conducted in Belgium and northern Italy. The insect fauna associated with I. pseudacorus at the sites surveyed comprised mostly incidental visitors and polyphagous feeders, with the exception of the sawfly Rhadinoceraea micans Klug (Hymenoptera: Tenthredinidae), the seed weevil Mononychus punctumalbum Herbst (Coleoptera: Curculionidae), and the flea beetle Aphthona nonstriata Goeze (Coleoptera: Chrysomelidae). The potential of these species for biocontrol was evaluated, and A. nonstriata was given highest priority. A population of this species was imported to quarantine in South Africa, where it is currently undergoing host-specificity testing. Importation of the two remaining candidates is expected shortly. In conclusion, the prospects for the biological control of I. pseudacorus appear promising.
- Full Text:
- Date Issued: 2020
- Authors: Minuti, Gianmarco , Coetzee, Julie A , Ngxande-Koza, Samella W , Hill, Martin P , Stiers, Iris
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417776 , vital:71485 , xlink:href="https://doi.org/10.1080/09583157.2020.1853050"
- Description: Native to Europe, North Africa and western Asia, Iris pseudacorus L. (Iridaceae) has invaded natural and human-modified wetlands worldwide. This species is considered a noxious weed in several countries including Argentina, South Africa and New Zealand. Its broad ecological tolerance, high resilience and reproductive potential make current mechanical and chemical control measures cost-ineffective, and biological control is considered a suitable alternative. In order to prioritise candidate biocontrol agents, a list of organisms reported to attack the plant within its native range has been assembled, and information about their host-range and damaging potential gathered from the literature. Furthermore, surveys for natural enemies of the plant were conducted in Belgium and northern Italy. The insect fauna associated with I. pseudacorus at the sites surveyed comprised mostly incidental visitors and polyphagous feeders, with the exception of the sawfly Rhadinoceraea micans Klug (Hymenoptera: Tenthredinidae), the seed weevil Mononychus punctumalbum Herbst (Coleoptera: Curculionidae), and the flea beetle Aphthona nonstriata Goeze (Coleoptera: Chrysomelidae). The potential of these species for biocontrol was evaluated, and A. nonstriata was given highest priority. A population of this species was imported to quarantine in South Africa, where it is currently undergoing host-specificity testing. Importation of the two remaining candidates is expected shortly. In conclusion, the prospects for the biological control of I. pseudacorus appear promising.
- Full Text:
- Date Issued: 2020
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