Oidium longipes, a new powdery mildew fungus on petunia in the USA: A potential threat to ornamental and vegetable solanaceous crops

L. Kiss, Tünde Jankovics, G. Kovács, Margery L. Daughtrey

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

This is the first North American report of Oidium longipes, an anamorphic powdery mildew species described recently in Europe. It was found on vegetatively propagated petunia grown in a commercial greenhouse in New Jersey, USA, where it caused a rapidly spreading disease. The pathogen might have originated offshore and may have already been distributed in the United States through horticultural trade. During field surveys in Europe, it was found on petunia in Hungary and Austria as well; this is the first report of O. longipes from these two countries. A detailed light microscopy study of American and European specimens of O. longipes, including freshly collected samples and authentic herbarium specimens, revealed that its conidiophore morphology is more variable than illustrated in the original species description or in subsequent works. Microcycle conidiation, a process not yet known to occur in powdery mildews, was repeatedly observed in O. longipes. The rDNA internal transcribed spacer (ITS) sequences were identical in colonies containing different conidiophore types as well as in a total of five specimens collected from petunia in the United States, Austria, Hungary, Germany, and Switzerland. A phylogenetic analysis of the ITS sequences revealed that the closest known relative of O. longipes is O. lycopersici, known to infect tomato only in Australia. Cross-inoculation tests showed that O. longipes from petunia heavily infected tobacco cv. Xanthi, while the tomato and eggplant cultivars tested were moderately susceptible to this pathogen. These results indicate that its spread represents a potential danger to a number of solanaceous crops. Our ad hoc field surveys conducted in 2006 and 2007 did not detect it outside New Jersey in the United States; all the other powdery mildew-infected petunias, collected in New York and Indiana, were infected by Podosphaera xanthii. In Europe, most of the powdery mildew-infected petunias examined in this study were infected by P. xanthii or Golovinomyces orontii. Our multiple inoculation tests revealed that the same petunia plants and even the same leaves can be infected concomitantly by O. longipes, O. neolycopersici, G. orontii, and P. xanthii. Thus, it is at present unclear to what extent O. longipes contributes to the powdery mildew epidemics that develop year after year on solanaceous plants in many parts of the world.

Original languageEnglish
Pages (from-to)818-825
Number of pages8
JournalPlant Disease
Volume92
Issue number5
DOIs
Publication statusPublished - May 2008

Fingerprint

Oidium
Petunia
powdery mildew
vegetables
fungi
crops
conidiophores
Austria
Hungary
internal transcribed spacers
tomatoes
Podosphaera
mildews
pathogens
eggplants
herbaria
Switzerland
light microscopy
tobacco
Germany

ASJC Scopus subject areas

  • Plant Science

Cite this

Oidium longipes, a new powdery mildew fungus on petunia in the USA : A potential threat to ornamental and vegetable solanaceous crops. / Kiss, L.; Jankovics, Tünde; Kovács, G.; Daughtrey, Margery L.

In: Plant Disease, Vol. 92, No. 5, 05.2008, p. 818-825.

Research output: Contribution to journalArticle

@article{ba11684fb7e14cd886887a20a94f6022,
title = "Oidium longipes, a new powdery mildew fungus on petunia in the USA: A potential threat to ornamental and vegetable solanaceous crops",
abstract = "This is the first North American report of Oidium longipes, an anamorphic powdery mildew species described recently in Europe. It was found on vegetatively propagated petunia grown in a commercial greenhouse in New Jersey, USA, where it caused a rapidly spreading disease. The pathogen might have originated offshore and may have already been distributed in the United States through horticultural trade. During field surveys in Europe, it was found on petunia in Hungary and Austria as well; this is the first report of O. longipes from these two countries. A detailed light microscopy study of American and European specimens of O. longipes, including freshly collected samples and authentic herbarium specimens, revealed that its conidiophore morphology is more variable than illustrated in the original species description or in subsequent works. Microcycle conidiation, a process not yet known to occur in powdery mildews, was repeatedly observed in O. longipes. The rDNA internal transcribed spacer (ITS) sequences were identical in colonies containing different conidiophore types as well as in a total of five specimens collected from petunia in the United States, Austria, Hungary, Germany, and Switzerland. A phylogenetic analysis of the ITS sequences revealed that the closest known relative of O. longipes is O. lycopersici, known to infect tomato only in Australia. Cross-inoculation tests showed that O. longipes from petunia heavily infected tobacco cv. Xanthi, while the tomato and eggplant cultivars tested were moderately susceptible to this pathogen. These results indicate that its spread represents a potential danger to a number of solanaceous crops. Our ad hoc field surveys conducted in 2006 and 2007 did not detect it outside New Jersey in the United States; all the other powdery mildew-infected petunias, collected in New York and Indiana, were infected by Podosphaera xanthii. In Europe, most of the powdery mildew-infected petunias examined in this study were infected by P. xanthii or Golovinomyces orontii. Our multiple inoculation tests revealed that the same petunia plants and even the same leaves can be infected concomitantly by O. longipes, O. neolycopersici, G. orontii, and P. xanthii. Thus, it is at present unclear to what extent O. longipes contributes to the powdery mildew epidemics that develop year after year on solanaceous plants in many parts of the world.",
author = "L. Kiss and T{\"u}nde Jankovics and G. Kov{\'a}cs and Daughtrey, {Margery L.}",
year = "2008",
month = "5",
doi = "10.1094/PDIS-92-5-0818",
language = "English",
volume = "92",
pages = "818--825",
journal = "Plant Disease",
issn = "0191-2917",
publisher = "American Phytopathological Society",
number = "5",

}

TY - JOUR

T1 - Oidium longipes, a new powdery mildew fungus on petunia in the USA

T2 - A potential threat to ornamental and vegetable solanaceous crops

AU - Kiss, L.

AU - Jankovics, Tünde

AU - Kovács, G.

AU - Daughtrey, Margery L.

PY - 2008/5

Y1 - 2008/5

N2 - This is the first North American report of Oidium longipes, an anamorphic powdery mildew species described recently in Europe. It was found on vegetatively propagated petunia grown in a commercial greenhouse in New Jersey, USA, where it caused a rapidly spreading disease. The pathogen might have originated offshore and may have already been distributed in the United States through horticultural trade. During field surveys in Europe, it was found on petunia in Hungary and Austria as well; this is the first report of O. longipes from these two countries. A detailed light microscopy study of American and European specimens of O. longipes, including freshly collected samples and authentic herbarium specimens, revealed that its conidiophore morphology is more variable than illustrated in the original species description or in subsequent works. Microcycle conidiation, a process not yet known to occur in powdery mildews, was repeatedly observed in O. longipes. The rDNA internal transcribed spacer (ITS) sequences were identical in colonies containing different conidiophore types as well as in a total of five specimens collected from petunia in the United States, Austria, Hungary, Germany, and Switzerland. A phylogenetic analysis of the ITS sequences revealed that the closest known relative of O. longipes is O. lycopersici, known to infect tomato only in Australia. Cross-inoculation tests showed that O. longipes from petunia heavily infected tobacco cv. Xanthi, while the tomato and eggplant cultivars tested were moderately susceptible to this pathogen. These results indicate that its spread represents a potential danger to a number of solanaceous crops. Our ad hoc field surveys conducted in 2006 and 2007 did not detect it outside New Jersey in the United States; all the other powdery mildew-infected petunias, collected in New York and Indiana, were infected by Podosphaera xanthii. In Europe, most of the powdery mildew-infected petunias examined in this study were infected by P. xanthii or Golovinomyces orontii. Our multiple inoculation tests revealed that the same petunia plants and even the same leaves can be infected concomitantly by O. longipes, O. neolycopersici, G. orontii, and P. xanthii. Thus, it is at present unclear to what extent O. longipes contributes to the powdery mildew epidemics that develop year after year on solanaceous plants in many parts of the world.

AB - This is the first North American report of Oidium longipes, an anamorphic powdery mildew species described recently in Europe. It was found on vegetatively propagated petunia grown in a commercial greenhouse in New Jersey, USA, where it caused a rapidly spreading disease. The pathogen might have originated offshore and may have already been distributed in the United States through horticultural trade. During field surveys in Europe, it was found on petunia in Hungary and Austria as well; this is the first report of O. longipes from these two countries. A detailed light microscopy study of American and European specimens of O. longipes, including freshly collected samples and authentic herbarium specimens, revealed that its conidiophore morphology is more variable than illustrated in the original species description or in subsequent works. Microcycle conidiation, a process not yet known to occur in powdery mildews, was repeatedly observed in O. longipes. The rDNA internal transcribed spacer (ITS) sequences were identical in colonies containing different conidiophore types as well as in a total of five specimens collected from petunia in the United States, Austria, Hungary, Germany, and Switzerland. A phylogenetic analysis of the ITS sequences revealed that the closest known relative of O. longipes is O. lycopersici, known to infect tomato only in Australia. Cross-inoculation tests showed that O. longipes from petunia heavily infected tobacco cv. Xanthi, while the tomato and eggplant cultivars tested were moderately susceptible to this pathogen. These results indicate that its spread represents a potential danger to a number of solanaceous crops. Our ad hoc field surveys conducted in 2006 and 2007 did not detect it outside New Jersey in the United States; all the other powdery mildew-infected petunias, collected in New York and Indiana, were infected by Podosphaera xanthii. In Europe, most of the powdery mildew-infected petunias examined in this study were infected by P. xanthii or Golovinomyces orontii. Our multiple inoculation tests revealed that the same petunia plants and even the same leaves can be infected concomitantly by O. longipes, O. neolycopersici, G. orontii, and P. xanthii. Thus, it is at present unclear to what extent O. longipes contributes to the powdery mildew epidemics that develop year after year on solanaceous plants in many parts of the world.

UR - http://www.scopus.com/inward/record.url?scp=44349181552&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=44349181552&partnerID=8YFLogxK

U2 - 10.1094/PDIS-92-5-0818

DO - 10.1094/PDIS-92-5-0818

M3 - Article

AN - SCOPUS:44349181552

VL - 92

SP - 818

EP - 825

JO - Plant Disease

JF - Plant Disease

SN - 0191-2917

IS - 5

ER -