Distribution, Population Dynamics and Sustainable Management of Plant-Parasitic Nematodes Associated with Cut-Flowers in Ethiopia
Distribution, Population Dynamics and Sustainable Management of Plant-Parasitic Nematodes Associated with Cut-Flowers in Ethiopia
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DissertationDate of Exam
28.08.2014Date of Publication
12.09.2014Advisor
Dehne, Heinz-WilhelmCo-Referee
Hallmann, JohannesMetadata
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Abstract
Plant-parasitic nematodes are a growing concern for the floriculture industry in Ethiopia. Two surveys were conducted during the wet season (August to September 2011) and dry season (April to May 2012) to assess the incidence of economically important plant-parasitic nematodes associated with major cut-flowers. Soil samples were collected from rose, carnation, gypsophila, freesia and statice. Thirteen nematode taxa viz. Criconemella, Ditylenchus, Helicotylenchus, Hemicycliophora, Meloidogyne, Merlinius, Longidorus, Paratrichodorus, Paratylenchus, Pratylenchus, Rotylenchus, Rotylenchulus and Tylenchorhynchus were detected. Roses harboured all of the genera. Helicotylenchus was found in all cut-flower species and Meloidogyne was found more frequently during the dry than the wet season.
Meloidogyne hapla was the most important root-knot nematode detected and reported here for the first time from Ethiopia. Pure cultures of this species were morphologically and molecularly characterized. For the latter, the D2-D3 expansion of the 28S ribosomal DNA and the region located between cytochrome oxidase unit II and the 16S rRNA gene of the mitochondria (mtDNA) were chosen. Phylogenetic comparison resulted in a highly supported clade containing the Ethiopian isolates of M. hapla together with M. hapla populations from other regions of the world. Female, male and second-stage juvenile (J2) morphology was in line with other descriptions of M. hapla with few exceptions. The female vulva slit was smaller than for the Hawaiian population and J2 body size was larger compared to previous descriptions from Hawaii and East Africa.
The host status of commonly grown cut-flowers in Ethiopia was assessed for M. hapla and M. incognita under greenhouse conditions. Overall, infected plants were less vigorous than non-infected plants. Meloidogyne hapla reproduced higher on roses than any other plant species assessed. Freesia appeared to be a poor host for M. hapla and M. incognita whiles all other cut-flower species were intermediate to good hosts for M. hapla and M. incognita.
The threshold level for M. hapla on Rosa corymbifera 'Laxa', R. multiflora and R. canina Inermis was assessed in pot experiments with increasing initial nematode densities from 0 to 128 J2 g-1 soil. M. hapla significantly reduced plant fresh weight of all three rose rootstock species independently of the initial nematode density. The minimum yield was below 0.73 and a tolerance limit of below 0.1 J2 g-1 soil. Nematode multiplication rate was highest on R. multiflora (24.39) followed by R. corymbifera 'Laxa' (4.34) and R. canina (3.62). Hence, all three rootstock species turned out to be sensitive to even low initial densities of M. hapla.
Ethanolic and aqueous extracts of native Rumex abyssinicus, Plumbago dawei and Maesa lanceolata significantly inhibited M. hapla in vitro and reduced nematode infection of tomato. Therefore, those botanical nematicides are a promising alternative for nematode control, especially since those plants are abundantly available throughout Ethiopia. Verteilung, Bevölkerungsdynamik und nachhaltige Bewirtschaftung von Pflanzenparasitäre Nematoden Verbunden mit Schnittblumen in Äthiopien
Pflanzenparasitäre Nematoden entwickeln sich zunehmend zu einem wirtschaftlichen Problem in der Schnittblumenproduktion Äthiopiens. Im Rahmen eines Monitorings während der Regenzeit 2011 (August bis September) und Trockenzeit 2012 (April bis Mai) wurden an Rosen, Nelken, Schleierkraut, Freesien und Strandflieder 13 wirtschaftlich bedeutende Nematodengattungen erfasst: Criconemella, Ditylenchus, Helicotylenchus, Hemicycliophora, Meloidogyne, Merlinius, Longidorus, Paratrichodorus, Paratylenchus, Pratylenchus, Rotylenchus, Rotylenchulus und Tylenchorhynchus. Alle Gattungen traten an Rosen auf. Helicotylenchus wurde an allen untersuchten Schnittblumenarten nachgewiesen und Meloidogyne war häufiger in der Trockenzeit als in der Regenzeit anzutreffen.
Meloidogyne hapla war die mit Abstand wirtschaftlich bedeutendste Nematodenart an Rosen in Äthiopien. Da M. hapla erstmals in Äthiopien nachgewiesen wurde, erfolgte eine vergleichende Charakterisierung der Äthiopischen Population von M. hapla mit Populationen aus anderen Ländern. Mittels molekularer Verfahren wurde die D2-D3 Extension der 28S ribosomale DNA und die Region zwischen der Cytochrome Oxidase Unit II und dem 16S rRNA Gen der Mitochondrien verglichen. Demnach war die Äthiopische Population von M. hapla sehr eng mit anderen Populationen verwandt. Auch morphologisch zeigten sich bei Weibchen, Männchen und dam zweiten Juvenilstadium nur geringe Unterschiede zwischen der Äthiopischen Population und den anderen Populationen.
Die in Äthiopien angebauten Schnittblumen wurden hinsichtlich ihres Wirtsstatus für M. hapla und M. incognita untersucht. Befallene Pflanzen waren weniger wüchsig als nicht befallene Pflanzen. Meloidogyne hapla konnte sich an Rosen besser vermehren als an allen anderen Schnittblumenarten. Freesien erwiesen sich als schlechte Wirte für M. hapla and M. incognita. Sonstige Schnittblumenarten erwiesen sich als mittelmäßige bis gute Wirte für die beiden Nematodenarten.
Die Schadschwelle für M. hapla an Rosa corymbifera 'Laxa', R. multiflora und R. canina Inermis wurde in Topfversuchen mit kontinuierlich ansteigenden Nematodendichten von 0 auf 128 J2 g-1 Boden ermittelt. Der minimale Ertrag lag bei etwa 0,73 und die Toleranzschwelle für Ertrag bei 0,1 J2 g-1 Boden. Die höchste Vermehrungsrate von M. hapla trat an R. multiflora (24,39) auf, gefolgt von R. corymbifera 'Laxa' (4,34) und R. canina (3,62). Somit erwiesen sich alle drei Unterlagensorten als sehr anfällig für M. hapla.
Äthanolische und wässrige Extrakte der in Äthiopien einheimischen Pflanzen Rumex abyssinicus, Plumbago dawei und Maesa lanceolata führten zu einer signifikanten Unterdrückung von M. hapla in vitro und reduzierten den Nematodenbefall an Tomate. Solch pflanzliche Extrakte könnten eine vielversprechende Alternative zur chemischen Bekämpfung darstellen, zumal die Pflanzen in Äthiopien weit verbreitet sind.
Meloidogyne hapla was the most important root-knot nematode detected and reported here for the first time from Ethiopia. Pure cultures of this species were morphologically and molecularly characterized. For the latter, the D2-D3 expansion of the 28S ribosomal DNA and the region located between cytochrome oxidase unit II and the 16S rRNA gene of the mitochondria (mtDNA) were chosen. Phylogenetic comparison resulted in a highly supported clade containing the Ethiopian isolates of M. hapla together with M. hapla populations from other regions of the world. Female, male and second-stage juvenile (J2) morphology was in line with other descriptions of M. hapla with few exceptions. The female vulva slit was smaller than for the Hawaiian population and J2 body size was larger compared to previous descriptions from Hawaii and East Africa.
The host status of commonly grown cut-flowers in Ethiopia was assessed for M. hapla and M. incognita under greenhouse conditions. Overall, infected plants were less vigorous than non-infected plants. Meloidogyne hapla reproduced higher on roses than any other plant species assessed. Freesia appeared to be a poor host for M. hapla and M. incognita whiles all other cut-flower species were intermediate to good hosts for M. hapla and M. incognita.
The threshold level for M. hapla on Rosa corymbifera 'Laxa', R. multiflora and R. canina Inermis was assessed in pot experiments with increasing initial nematode densities from 0 to 128 J2 g-1 soil. M. hapla significantly reduced plant fresh weight of all three rose rootstock species independently of the initial nematode density. The minimum yield was below 0.73 and a tolerance limit of below 0.1 J2 g-1 soil. Nematode multiplication rate was highest on R. multiflora (24.39) followed by R. corymbifera 'Laxa' (4.34) and R. canina (3.62). Hence, all three rootstock species turned out to be sensitive to even low initial densities of M. hapla.
Ethanolic and aqueous extracts of native Rumex abyssinicus, Plumbago dawei and Maesa lanceolata significantly inhibited M. hapla in vitro and reduced nematode infection of tomato. Therefore, those botanical nematicides are a promising alternative for nematode control, especially since those plants are abundantly available throughout Ethiopia.
Pflanzenparasitäre Nematoden entwickeln sich zunehmend zu einem wirtschaftlichen Problem in der Schnittblumenproduktion Äthiopiens. Im Rahmen eines Monitorings während der Regenzeit 2011 (August bis September) und Trockenzeit 2012 (April bis Mai) wurden an Rosen, Nelken, Schleierkraut, Freesien und Strandflieder 13 wirtschaftlich bedeutende Nematodengattungen erfasst: Criconemella, Ditylenchus, Helicotylenchus, Hemicycliophora, Meloidogyne, Merlinius, Longidorus, Paratrichodorus, Paratylenchus, Pratylenchus, Rotylenchus, Rotylenchulus und Tylenchorhynchus. Alle Gattungen traten an Rosen auf. Helicotylenchus wurde an allen untersuchten Schnittblumenarten nachgewiesen und Meloidogyne war häufiger in der Trockenzeit als in der Regenzeit anzutreffen.
Meloidogyne hapla war die mit Abstand wirtschaftlich bedeutendste Nematodenart an Rosen in Äthiopien. Da M. hapla erstmals in Äthiopien nachgewiesen wurde, erfolgte eine vergleichende Charakterisierung der Äthiopischen Population von M. hapla mit Populationen aus anderen Ländern. Mittels molekularer Verfahren wurde die D2-D3 Extension der 28S ribosomale DNA und die Region zwischen der Cytochrome Oxidase Unit II und dem 16S rRNA Gen der Mitochondrien verglichen. Demnach war die Äthiopische Population von M. hapla sehr eng mit anderen Populationen verwandt. Auch morphologisch zeigten sich bei Weibchen, Männchen und dam zweiten Juvenilstadium nur geringe Unterschiede zwischen der Äthiopischen Population und den anderen Populationen.
Die in Äthiopien angebauten Schnittblumen wurden hinsichtlich ihres Wirtsstatus für M. hapla und M. incognita untersucht. Befallene Pflanzen waren weniger wüchsig als nicht befallene Pflanzen. Meloidogyne hapla konnte sich an Rosen besser vermehren als an allen anderen Schnittblumenarten. Freesien erwiesen sich als schlechte Wirte für M. hapla and M. incognita. Sonstige Schnittblumenarten erwiesen sich als mittelmäßige bis gute Wirte für die beiden Nematodenarten.
Die Schadschwelle für M. hapla an Rosa corymbifera 'Laxa', R. multiflora und R. canina Inermis wurde in Topfversuchen mit kontinuierlich ansteigenden Nematodendichten von 0 auf 128 J2 g-1 Boden ermittelt. Der minimale Ertrag lag bei etwa 0,73 und die Toleranzschwelle für Ertrag bei 0,1 J2 g-1 Boden. Die höchste Vermehrungsrate von M. hapla trat an R. multiflora (24,39) auf, gefolgt von R. corymbifera 'Laxa' (4,34) und R. canina (3,62). Somit erwiesen sich alle drei Unterlagensorten als sehr anfällig für M. hapla.
Äthanolische und wässrige Extrakte der in Äthiopien einheimischen Pflanzen Rumex abyssinicus, Plumbago dawei und Maesa lanceolata führten zu einer signifikanten Unterdrückung von M. hapla in vitro und reduzierten den Nematodenbefall an Tomate. Solch pflanzliche Extrakte könnten eine vielversprechende Alternative zur chemischen Bekämpfung darstellen, zumal die Pflanzen in Äthiopien weit verbreitet sind.
Subjects
28S rRNA, plant extracts, host status, Meloidogyne hapla, mtDNA, roses
Classification (DDC)
630 Landwirtschaft, VeterinärmedizinMeressa, Beira Hailu: Distribution, Population Dynamics and Sustainable Management of Plant-Parasitic Nematodes Associated with Cut-Flowers in Ethiopia. - Bonn, 2014. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5n-37461
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5n-37461
@phdthesis{handle:20.500.11811/5857,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5n-37461,
author = {{Beira Hailu Meressa}},
title = {Distribution, Population Dynamics and Sustainable Management of Plant-Parasitic Nematodes Associated with Cut-Flowers in Ethiopia},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2014,
month = sep,
note = {Plant-parasitic nematodes are a growing concern for the floriculture industry in Ethiopia. Two surveys were conducted during the wet season (August to September 2011) and dry season (April to May 2012) to assess the incidence of economically important plant-parasitic nematodes associated with major cut-flowers. Soil samples were collected from rose, carnation, gypsophila, freesia and statice. Thirteen nematode taxa viz. Criconemella, Ditylenchus, Helicotylenchus, Hemicycliophora, Meloidogyne, Merlinius, Longidorus, Paratrichodorus, Paratylenchus, Pratylenchus, Rotylenchus, Rotylenchulus and Tylenchorhynchus were detected. Roses harboured all of the genera. Helicotylenchus was found in all cut-flower species and Meloidogyne was found more frequently during the dry than the wet season.
Meloidogyne hapla was the most important root-knot nematode detected and reported here for the first time from Ethiopia. Pure cultures of this species were morphologically and molecularly characterized. For the latter, the D2-D3 expansion of the 28S ribosomal DNA and the region located between cytochrome oxidase unit II and the 16S rRNA gene of the mitochondria (mtDNA) were chosen. Phylogenetic comparison resulted in a highly supported clade containing the Ethiopian isolates of M. hapla together with M. hapla populations from other regions of the world. Female, male and second-stage juvenile (J2) morphology was in line with other descriptions of M. hapla with few exceptions. The female vulva slit was smaller than for the Hawaiian population and J2 body size was larger compared to previous descriptions from Hawaii and East Africa.
The host status of commonly grown cut-flowers in Ethiopia was assessed for M. hapla and M. incognita under greenhouse conditions. Overall, infected plants were less vigorous than non-infected plants. Meloidogyne hapla reproduced higher on roses than any other plant species assessed. Freesia appeared to be a poor host for M. hapla and M. incognita whiles all other cut-flower species were intermediate to good hosts for M. hapla and M. incognita.
The threshold level for M. hapla on Rosa corymbifera 'Laxa', R. multiflora and R. canina Inermis was assessed in pot experiments with increasing initial nematode densities from 0 to 128 J2 g-1 soil. M. hapla significantly reduced plant fresh weight of all three rose rootstock species independently of the initial nematode density. The minimum yield was below 0.73 and a tolerance limit of below 0.1 J2 g-1 soil. Nematode multiplication rate was highest on R. multiflora (24.39) followed by R. corymbifera 'Laxa' (4.34) and R. canina (3.62). Hence, all three rootstock species turned out to be sensitive to even low initial densities of M. hapla.
Ethanolic and aqueous extracts of native Rumex abyssinicus, Plumbago dawei and Maesa lanceolata significantly inhibited M. hapla in vitro and reduced nematode infection of tomato. Therefore, those botanical nematicides are a promising alternative for nematode control, especially since those plants are abundantly available throughout Ethiopia.},
url = {https://hdl.handle.net/20.500.11811/5857}
}
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5n-37461,
author = {{Beira Hailu Meressa}},
title = {Distribution, Population Dynamics and Sustainable Management of Plant-Parasitic Nematodes Associated with Cut-Flowers in Ethiopia},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2014,
month = sep,
note = {Plant-parasitic nematodes are a growing concern for the floriculture industry in Ethiopia. Two surveys were conducted during the wet season (August to September 2011) and dry season (April to May 2012) to assess the incidence of economically important plant-parasitic nematodes associated with major cut-flowers. Soil samples were collected from rose, carnation, gypsophila, freesia and statice. Thirteen nematode taxa viz. Criconemella, Ditylenchus, Helicotylenchus, Hemicycliophora, Meloidogyne, Merlinius, Longidorus, Paratrichodorus, Paratylenchus, Pratylenchus, Rotylenchus, Rotylenchulus and Tylenchorhynchus were detected. Roses harboured all of the genera. Helicotylenchus was found in all cut-flower species and Meloidogyne was found more frequently during the dry than the wet season.
Meloidogyne hapla was the most important root-knot nematode detected and reported here for the first time from Ethiopia. Pure cultures of this species were morphologically and molecularly characterized. For the latter, the D2-D3 expansion of the 28S ribosomal DNA and the region located between cytochrome oxidase unit II and the 16S rRNA gene of the mitochondria (mtDNA) were chosen. Phylogenetic comparison resulted in a highly supported clade containing the Ethiopian isolates of M. hapla together with M. hapla populations from other regions of the world. Female, male and second-stage juvenile (J2) morphology was in line with other descriptions of M. hapla with few exceptions. The female vulva slit was smaller than for the Hawaiian population and J2 body size was larger compared to previous descriptions from Hawaii and East Africa.
The host status of commonly grown cut-flowers in Ethiopia was assessed for M. hapla and M. incognita under greenhouse conditions. Overall, infected plants were less vigorous than non-infected plants. Meloidogyne hapla reproduced higher on roses than any other plant species assessed. Freesia appeared to be a poor host for M. hapla and M. incognita whiles all other cut-flower species were intermediate to good hosts for M. hapla and M. incognita.
The threshold level for M. hapla on Rosa corymbifera 'Laxa', R. multiflora and R. canina Inermis was assessed in pot experiments with increasing initial nematode densities from 0 to 128 J2 g-1 soil. M. hapla significantly reduced plant fresh weight of all three rose rootstock species independently of the initial nematode density. The minimum yield was below 0.73 and a tolerance limit of below 0.1 J2 g-1 soil. Nematode multiplication rate was highest on R. multiflora (24.39) followed by R. corymbifera 'Laxa' (4.34) and R. canina (3.62). Hence, all three rootstock species turned out to be sensitive to even low initial densities of M. hapla.
Ethanolic and aqueous extracts of native Rumex abyssinicus, Plumbago dawei and Maesa lanceolata significantly inhibited M. hapla in vitro and reduced nematode infection of tomato. Therefore, those botanical nematicides are a promising alternative for nematode control, especially since those plants are abundantly available throughout Ethiopia.},
url = {https://hdl.handle.net/20.500.11811/5857}
}
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