May 22, 2003

 

Send Quality Samples to the NDSU Plant Diagnostic Lab

Sending high quality samples to the North Dakota State University Diagnostic Lab will help ensure an accurate diagnosis and speedier response to your problem according to Cheryl Biller, NDSU plant diagnostician. "A high quality sample mailed to the lab will include the plant or plant parts, a name, address, contact information and some background information about the problem. A very low quality sample will come in a box with a piece of paper saying please diagnose."

Questions to consider for background information include:

• How many plants are affected or how much of the field?
• What is the primary concern?
• When was the first observation that indicated a problem?
• Is there a pattern either in a field or on a single plant?
• Were pesticides, herbicides, insecticides, fungicides used?
• Was fertilizer applied?
• Is there a topographical correlation with the symptoms?
• What plant or crop was previously grown on the site?
• What where the recent weather conditions?

Packaging of a sample will vary depending on the problem. Sending several leaves that show the symptom or symptoms layered in dry paper toweling or between sheets of paper is often sufficient if the plants in question show foliar symptoms. "If there are symptoms throughout the plant, or whenever reasonable, a whole plant or two should be sent," Biller says. "The root ball can be wrapped or enclosed in plastic but the foliage should be left unwrapped and the plants placed in a box to be mailed."

Packing material or newspapers should be used if the plants are going to shift significantly in the box or padded envelope.

For trees or other woody plant species, snipping off a branch or twig is appropriate as long as it identifies the problem. Biller notes that it is often helpful to also see a branch or twig that appears normal. "If a normal sample is not included, the background and description of the problem is even more important."

If a root problem is suspected, dig up the plants and include some of the attached soil.

For plant identification, send as much of the plant as possible. A scanned photo or a picture from a digital camera may provide adequate views for a diagnostic identification. The key to getting a specific, accurate identification from a digital sample is a focused picture. Biller suggests taking several shots, from different angles and showing different sides. The digital photos should also be viewed before sending.

Costs vary depending upon the test. A routine diagnosis is $15 for North Dakota residents and $25 for Minnesota residents. Special tests are $30. Call for availability and price regarding chemical residue testing. A routine diagnosis will generally take two to three days to complete. Chemical reside testing is usually completed in five to seven days while special tests and cultures may take a week or two.

If you send a diagnostic lab form with the sample, be sure to fill it out as completely as possible. If you would like a form or have any questions on how to package or send a sample, call the lab at (701) 231-7854 or e-mail diaglab@ndsuext.nodak.edu

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Source: Cheryl Biller, (701) 231-7854, diaglab@ndsuext.nodak.edu
Editor: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu