Welcome to the late blight sample online reporting site. Our goal is to ensure efficient processing of samples submitted for genotypic analysis. If you would like to know what genotype of the pathogen occurs on your farm then submit a sample following the procedures below.
Samples must be reported online before the sample is submitted and a form that is generated from your submission must be included with the sample. The disease report will generate a sample number which should be written directly on the sample bag when it is sent to the lab and this number can be used to track your sample. Additionally, you can easily enter the information necessary for sample submission form from the field using your laptop, smart phone or tablet.
Samples may be sent fresh or dry. Fresh samples will require a copy of our APHIS permit inside the package (see Fresh Sample Collection below). Dry samples do not require an APHIS permit for transport from locations outside of North Carolina, but we will be unable to isolate the pathogen from the leaves for any additional testing beyond genetic testing/genotyping.
Sample Collection: Dry
In the event a sample cannot be sent immediately, leaves can be preserved using drying/pressing methods or through the use of FTA cards. FTA cards are the fastest method of preserving leaf tissue for further analysis and can be purchased through Qiagen. Instructions on how to use FTA cards can be found in this PDF or through Euroblight.
If FTA cards are unavailable, leaves can be dried for genotyping.
How to dry:
- Choose a minimum of 5 turgid leaflets with actively sporulating lesions. Small lesions are best. These leaflets should be collected from several locations within a field when possible.
- Place the leaflets between sheets of newspaper. Placing additional layers of absorbent material outside of the newspaper/leaf sandwich, such as paper towels or filter paper, can help with the drying process. Additional layers of cardboard can be used to give the newspaper/leaf sandwich structure. If you have access to a leaf press you can use this to complete the drying process.
- Place something heavy such as a large book on top of the sandwich. If you are using a plant press, tighten the press to apply the pressure needed. If possible, complete the drying process in a warm, dry place. This has the advantage of reducing the amount of time needed to dry the leaves.
- Check the leaves after 2-3 days. If dry, place the leaves in a labeled envelope (include your USABlight sample number). Mail the sample to:
Jean Ristaino
2323 Plant Sciences Building, Campus Box 7825
840 Oval Drive
North Carolina State University
Raleigh, NC 27606
Sample Collection: Fresh
When sending late blight samples from tomato, potato or other hosts (petunia or solanaceous weeds), it is best to send leaf tissue when possible. We have had much greater success with our assays using sporangia (pathogen spores) from leaf tissue rather than from fruit or tubers.
If you do send fruit or tubers please send them in a separate bag or shipment — so that they do not crush the leaf tissue in transit. If you want a rapid identification, it’s crucial that the there be sporulation from the infected tissue.
What to send:
- A minimum of 5 turgid leaflets with actively sporulating lesions. Small lesions are best. These leaflets should be collected from several locations within a field when possible. If you can, please send ten leaflets (or multiple whole leaves) so that some leaves can be dried and archived.
- Place the foliage in an air-tight dry plastic (Ziploc) bag with a cushion of air – so the foliage doesn’t get crushed in transit. It’s best to use a small shipping box rather than an envelope, PLEASE write the sample number on the bag.
- Send the sample immediately upon collection. If you must “hold” the sample overnight, keep it at 4-10C.
- Include the completed sample submission form.
- IMPORTANT! If you are sending the sample from one state to another (across a state line), you must include a copy of the appropriate APHIS permit that was sent to you via e-mail. If you do not have this permit, please contact Jean Ristaino (919-515-3257 or jbr@ncsu.edu ) or the lab you are sending the sample to.
- Mail the sample via overnight mail to:
Jean Ristaino
2323 Plant Sciences Building, Campus Box 7825
840 Oval Drive
North Carolina State University
Raleigh, NC 27606
If you suspect multiple sources of pathogen inoculum in a single field, please submit one sample for each area of interest. We will use the best lesion from each sample to perform genotypic assays. Taking sporangia directly from leaf tissue will speed up the analysis by at least 5 days. We will culture some of the isolates we receive, but not all. If there is a special reason that this particular isolate should be cultured, please let us know.
If you have questions about the sampling protocol, please do not hesitate to contact Jean or Amanda (acsavill@ncsu.edu) from the Ristaino genotyping lab.