How do I sample?

Late Blight Sample Collection & Submission Protocol

Welcome to the late blight sample online reporting site. Our goal is to ensure efficient processing of samples submitted for genotypic analysis. These instructions were last updated on July 24, 2014.  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, and a form that is generated from your submission must be included with the sample. The advantage to reporting the sample on-line is that you will receive 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.

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:

  1. 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.
  2. 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.
  3. Send the sample immediately upon collection. If you must “hold” the sample overnight, keep it at 4-10C.
  4. Include the completed sample submission form.
  5. 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 Chris Smart (315-787-2441 or cds14@cornell.edu ) or the lab you are sending the sample to.
  6. Mail the sample via overnight mail to:

 

Bill Fry
Cornell University
334 Plant Science Bldg
Ithaca, NY 14853


E-mail: wef1@cornell.edu
Office Phone: 607-255-7863
Lab Phone: 607-255-3188


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 the appropriate lab above.