By Tracey Sliva B.Sc., M.L.T., Plant Health Technician, Regina
June 2022
The growing season is upon Saskatchewan and the Crop Protection Laboratory (CPL) is preparing for sample submissions. Different samples sent to the lab have different guidelines for preparation for submission.
Dutch Elm Disease (DED) testing is conducted on suspected diseased elms between June 1 and August 31. Samples are tested for Ophiostoma novo-ulmi, the fungus that causes DED. Testing is done free of charge for Saskatchewan residents and out-of-province samples are not accepted. For accurate testing, the CPL requires samples that are from a branch showing symptoms of wilting or flagging. Samples must be smooth, straight branches without cankers or knots and must not be dried out or dead. Ensure three to four branches from each suspected diseased tree are sampled and that the branches are one to 1.5 cm in diameter and 10 to 15 cm long. No leaves, twigs or large branches are to be sent to the CPL. If sampling more than one tree, ensure your tools are sterilized between trees. Make sure to keep each sample separate and have each individual tree submission clearly labelled. Once you have taken the sample, it is important to submit it to the CPL as soon as possible. Each individual tree/sample requires its own submission form be completed. Samples will not be accepted without a form. The new deadline for sample submission is August 31.
Plant disease specimens can be submitted throughout the growing season. When sampling, choose specimens showing various stages of disease symptoms from light to severe. It is also important to include some healthy specimens for comparison. Whole plants including roots should be submitted to ensure an accurate diagnosis. Place roots into a damp paper towel and put this portion into a plastic bag and tie it off at the base of the stem. Leave the above ground parts loosely packed in dry paper towel. Ensure all sections of the Plant Disease Diagnosis Request Form are complete and submitted along with the sample. If the form is not entirely filled, this may delay your results, as we will need to contact you for additional information.
Weed and plant identification samples should be submitted as pressed plants. Samples should be prepared for submission by placing the sample between dry absorbent paper (e.g., newspaper) on a flat surface and then pressing by adding weight on top of the plants in the paper. Pressed plants should be checked for moisture, and you should replace the paper if it is wet. Checking for moisture and replacing the paper is more frequently required in the early stages of pressing. Once the plants are dry, they should be placed in rigid containers to prevent damage to the specimens during shipping. Placing dried specimens between rigid pieces of cardboard is effective. Plants requiring urgent identification may be shipped immediately without pressing. These samples can be prepared for submission by loosely wrapping the sample in dry paper towel to prevent damage during shipping. A rigid cardboard container, containing packing materials to prevent movement in shipping is appropriate. Ensure a completed Weed and Plant Identification Form accompanies the sample.