Ash dieback - Hymenoscyphus fraxineus
EEffective: April 8, 2014 - January 21, 2015
Resources:
Pest Tracker
CAPS Pest Datasheet
Screening Aids:
Taxonomic Position:
Incertae sedis : Incertae sedis
Pest Type:
Fungi
Pest Code (NAPIS):
FDACCOZ
| No manual – See Host Matrix |
These Approved Methods are appropriate for:
2015
Major Hosts identified in the Host Matrix:
Ash
This list includes important economic or environmental hosts but does not represent all major hosts of the pest. Check CAPS pest datasheet for complete list of hosts.
This list includes important economic or environmental hosts but does not represent all major hosts of the pest. Check CAPS pest datasheet for complete list of hosts.
Pest is vectored by:
No known vector.
Survey
Approved Method(s):
| Method | Instructions | NAPIS Survey Method |
|---|---|---|
| Visual | Collect symptomatic plant material. |
3031 - General Visual Observation |
Signs:
No specific signs are present.
Symptoms:
Shoot, twig, and branch dieback, wilting, leaf and bark lesions, collar necrosis, and gray to brown discoloration of the wood.
Key Diagnostics
ID/Diagnostic: Morphological
Morphological: Most frequently isolated on malt extract agar (supplemented with streptomycin sulfate) from the leading edge of discolored wood and necrotic leaf petioles, but rarely from necrotic bark.
Kowalski (2006) notes that C. fraxinea differs from other species of Chalara by its small, short, cylindrical phialoconidia extruded in chains or in slimy droplets, morphological features of the phialophores, and by colony characteristics.
Kowalski (2006) notes that C. fraxinea differs from other species of Chalara by its small, short, cylindrical phialoconidia extruded in chains or in slimy droplets, morphological features of the phialophores, and by colony characteristics.
Mistaken Identities:
Other Chalara species
In Progress / Literature-based Diagnostics:
Molecular: Bakys et al. (2009) combined PCR amplification of the ITS region of the ribosomal genes with terminal restriction fragment length polymorphism (T-RFLP) to determine which pathogens existed on Fraxinus excelsior in Sweden. In order to identify taxa in the T-RFLP profiles, PCR products were cloned, enabling sequencing of the ITS region of the rDNA genes for individual taxa within the mixed sample, and subsequent identification by database comparison.
Johansson et al. (2010) developed a set of species-specific PCR primers, based on ITS sequences, to detect C. fraxinea in plant (Fraxinus excelsior) tissue.
Real-time PCR: Ioos et al. (2009) developed a real-time PCR for detection of C. fraxinea in planta . Species-specific polymorphisms observed within the ITS region were used to design a primer pair and a dual-labeled probe for use in a real-time PCR assay for the detection of C. fraxinea. In silico and in vitro assessments showed that the PCR could detect as little as 20 fg of C. fraxinea DNA.
Chandelier et al. (2010) developed a real-time PCR for the detection of C. fraxinea from woody tissues. A procedure for DNA extraction from woody tissues using an electric drill yielded DNA of appropriate quality for DNA extraction. PCR primers and Taqman probes were developed based on the internal transcribed spacer (ITS) region of a multi-copy gene rDNA. The primers amplified an 81 bp fragment from C. fraxinea. The limit of detection was 5 pg of genomic DNA per PCR.
Johansson et al. (2010) developed a set of species-specific PCR primers, based on ITS sequences, to detect C. fraxinea in plant (Fraxinus excelsior) tissue.
Real-time PCR: Ioos et al. (2009) developed a real-time PCR for detection of C. fraxinea in planta . Species-specific polymorphisms observed within the ITS region were used to design a primer pair and a dual-labeled probe for use in a real-time PCR assay for the detection of C. fraxinea. In silico and in vitro assessments showed that the PCR could detect as little as 20 fg of C. fraxinea DNA.
Chandelier et al. (2010) developed a real-time PCR for the detection of C. fraxinea from woody tissues. A procedure for DNA extraction from woody tissues using an electric drill yielded DNA of appropriate quality for DNA extraction. PCR primers and Taqman probes were developed based on the internal transcribed spacer (ITS) region of a multi-copy gene rDNA. The primers amplified an 81 bp fragment from C. fraxinea. The limit of detection was 5 pg of genomic DNA per PCR.
References
- Bakys, R., Vesaitis, R., Barklund, P., Ihrmark, K., and Stenlid, J. 2009. Investigations concerning the role of Chalara fraxinea in declining Fraxinus excelsior . Plant Pathology 58: 284-292.
- Chandelier, A., Andre, F., and Laurent, F. 2010. Detection of Chalara fraxinea in common ash (Fraxinus excelsior) using real-time PCR. For. Path. 40: 87-95.
- Ioos, R., Kowalski, T., Husson, and C., Holdenrieder, O. 2009. Rapid in planta detection of Chalara fraxinea by a real-time PCR assay using a dual-labeled probe. Eur. J. Plant. Pathol. 125: 329-335.
- Johansson, S.B.K., Vasaitis, R., Ihrmark, K., Barklund, P, and Stenlid, J. 2010. Detection of Chalara fraxinea from tissue of Fraxinus excelsior using species-specific ITS primers. For. Path. 40: 111-115.
- Kowalski, T. 2006. Chalara fraxinea sp. nov. associated with dieback of ash (Fraxinus excelsior) in Poland. For. Path. 36: 264-270.