Don’t guess what’s causing your plants to be sick—we can help! Back »

Figure 1. A wheat sample sent to the diagnostic clinic for suspected herbicide drift injury. The actual cause of symptoms was Wheat streak mosaic virus.

Written collaboratively by Emmanuel Byamukama and Connie Tande.

Plant Disease Diagnostic Services

Effective plant disease management starts with proper disease diagnosis. Several plant diseases, nutrient deficiency or toxicity, and other disorders can elicit similar symptoms. It is therefore important to be absolutely sure what is causing the problem before making a decision on the management strategy.

SDSU Plant Diagnostic Clinic
The South Dakota State University Plant Diagnostic Clinic (SDSU-PDC) provides plant disease, and insect and plant disorder diagnostic services throughout the year. Submit your sample so you can know exactly what is causing the problem. Samples can be sent to the clinic via the post office or can be dropped off at campus. SDSU Extension county offices and regional centers also have mailers and information on how to send samples to the clinic.

Collecting & Submitting Samples

An accurate diagnosis is influenced by the quality of the sample. When collecting a sample for diagnosis, do not send a rotten or dried sample. It is difficult to isolate the actual cause of the problem in damaged samples. Also do not put the sample on the car dashboard or leave in the back of the truck for a long time. Sometimes symptoms may develop on the leaves when the problem is coming from the roots. Therefore, it is best to carefully dig out symptomatic plants and send in whole plant samples.

Mail the sample as soon as possible or drop off where possible (contact info below). Do not mail samples on Thursday or Friday since these samples are likely not to be delivered until Monday. A tall plant sample may be carefully cut into smaller sections for easy packaging but leaving lower nodes and roots intact. Use the Sample Submission Form to provide additional information that may help in the diagnosis process.

South Dakota State University
153 Plant Diagnostic Clinic (SPSB), Box 2108
Brookings, SD 57007
Phone: 605.688.5545
Fax: 605.688.4024
Email Website

Services & Fees

Free Soybean Testing
The SDSU Extension Plant Pathology Program currently has a grant, courtesy of the South Dakota Soybean Research and Promotion Council, to provide soybean sample diagnosis at no cost for South Dakota soybean growers. This includes soil for SCN testing as well as soybean plant sample diagnosis.

Other Crop Samples
Other crop samples have a fee associated with the diagnosis. The cost varies depending on the type of the test to be performed. Visit the SDSU-PDC Services and Fees website for more information.

The Bottom Line

Accurate plant disease diagnosis not only will result in effective disease management but may also save producers from unnecessary in-field pesticide application such as when the causal agent is bacteria, nematodes or virus, in which case nothing can be applied in season.

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