January 26, 2018

Sample Collection and Assistance for Disease Identification

By: Rebecca A. Melanson, MSU Extension Plant Pathologist, Central MS Research and Extension Center, Raymond, MS

     Diagnosis is the first step in disease management. It is important to know what disease and pathogen is affecting a plant or crop so that appropriate disease management actions can be taken. When seeking assistance from county agents or specialists, it is important to provide relevant information that can help your local county agent or specialist to identify the problem in a timely manner and determine the best management options. It is always a good idea to provide at least the following information: the affected plant host and variety, the extent of the damage, a description of the symptoms, and your preferences for disease management, which may range from conventional to strictly organic. Additional information such as disease history and recent pesticide use is also valuable.

     Often times, digital images (photos) of plants are also received from growers or homeowners wanting to know what is wrong with their plant. These images can be very valuable and provide additional information regarding a situation, but it is often not possible to diagnose a disease problem from a digital image. Information about the types of images that are most useful and examples of good images are available in MSU Extension publication P3022 Taking Photos of Plant Disease Problems. If sending photos to your local county agent or specialist, please remember to make sure that your photos are in focus and that you also provide the information requested above.

     Despite the valuable information that can be provided through words and images, it is often still necessary to examine a physical sample for diagnosis. Samples submitted for diagnosis should not be in an advanced stage of decay. They should also be fresh and arrive undamaged. Instructions for collecting and packaging samples for diagnosis are available in MSU Exteension publication M1562 How to Collect and Package Plant Disease Specimens for Diagnosis.

(The majority of this article originally appeared in the April 2017 issue of the North MS Fruit and Vegetable Newsletter.)