General Tips When Scouting and Sampling Agricultural Crops
While inspecting the issue, take pictures of the symptoms (close-up and general distribution in the field, greenhouse, high tunnel, garden, landscape, etc.). Please make sure that the pictures are high quality and in focus. Use the macro option in your camera (tulip icon in most cameras and smart phone cameras) for close-ups. Attach the pictures to an email to pidc@iastate.edu and in the subject include submitter last name, crop/plant and sample submission date (MM/DD/YY). Example: Smith-pepper-5/20/17.
Collect several samples. Select plants from areas where symptoms are starting, developing and developed. Avoid plants with advanced symptoms. A completely wilted or dead plant is not a good subject to submit.
When submitting a plant, roots and all, make sure the soil is contained, so it does not make contact with the foliage. Keep in mind we do not test for herbicide residue, nutrient levels in the foliage or soil, or these for pathogens (organisms that cause disease) in soil samples.
Field Crops
Seedlings: Send several whole plants, roots and all. Be sure to dig up the roots rather than pulling the plant from the ground. Watch our video “Sampling For Seedling Disease”
Foliar diseases: Send 6-10 leaves showing disease symptoms with varying severity.
Root rots: Collect 2-3 whole plants. Be sure to dig the roots rather than pulling the plants from the ground. When packaging whole plants for delivery make sure to bag the roots to prevent soil from covering the plant foliage. Watch our video Collecting Whole Plants For Plant Problem Diagnosis
It is also important to remember above ground symptoms can be caused by diseased roots. If you are unsure of what the problem might be, send in 2-3 whole plant samples. All samples should be wrapped in dry newspaper/paper towels. Never add water to a sample. Other details to include are cropping history, the pattern of symptoms in the field, chemical history, and cropping history.
Corn Tar Spot Survey (University of Illinois)
