Articles
PAULOWNIA WITCHES’-BROOM DISEASE IMPORTANT IN EAST ASIA
Article number
496_6
Pages
63 – 68
Language
Abstract
Paulownia, native to China, has been planted as a superior tree species for more than 2,000 years in East Asia.
It is highly suitable and popular as an intercropping species in modern agroforestry and is used commonly for urban shelterbelts, due to its rapid growth and attractive high canopy formation.
Paulownia witches’-broom (PaWB), one of the first phytoplasma diseases (Doi et al., 1967), has existed in East Asia for many years.
Once affected with PaWB, tree growth and vigor are greatly reduced and a severe decline results in premature death of the tree.
The wood of infected tree is of poor quality and often unfit for commercial use.
The PaWB agent is mainly disseminated by insect vectors Halyomorpha mista, H. halys and H. picus and vegetatively propagative materials such as root cuttings as well as by grafting and by dodder but not through seeds.
Polymerase chain reaction (PCR) assays are highly effective in detecting low DNA concentrations of PaWB phytoplasma known to occur in irregular patterns in diseased paulownia plants.
With regard to the genetic identity of PaWB phytoplasma, the isolates from China, Korea and Japan share the same 16S rRNA genes and belong to 16S RNA group I (aster yellows and related phytoplasmas). For PaWB control, an integrated disease management system must be established by continuous integration of a variety of carefully evaluated strategies, including field resistant clonal selections from paulownia gene banks and creation of disease-free nurseries.
It is highly suitable and popular as an intercropping species in modern agroforestry and is used commonly for urban shelterbelts, due to its rapid growth and attractive high canopy formation.
Paulownia witches’-broom (PaWB), one of the first phytoplasma diseases (Doi et al., 1967), has existed in East Asia for many years.
Once affected with PaWB, tree growth and vigor are greatly reduced and a severe decline results in premature death of the tree.
The wood of infected tree is of poor quality and often unfit for commercial use.
The PaWB agent is mainly disseminated by insect vectors Halyomorpha mista, H. halys and H. picus and vegetatively propagative materials such as root cuttings as well as by grafting and by dodder but not through seeds.
Polymerase chain reaction (PCR) assays are highly effective in detecting low DNA concentrations of PaWB phytoplasma known to occur in irregular patterns in diseased paulownia plants.
With regard to the genetic identity of PaWB phytoplasma, the isolates from China, Korea and Japan share the same 16S rRNA genes and belong to 16S RNA group I (aster yellows and related phytoplasmas). For PaWB control, an integrated disease management system must be established by continuous integration of a variety of carefully evaluated strategies, including field resistant clonal selections from paulownia gene banks and creation of disease-free nurseries.
Publication
Authors
C. Hiruki
Keywords
Mollicutes, Phytoplasma, agroforestry, urban tree, disease management
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