By Nathan Kleczewski
Extension Plant Pathologist
Often, late season issues result in the submission of senesced, dead, or decomposing samples to extension plant pathologists or diagnostic clinics in the hope that an answer to a potential issue can be derived from such samples. Unfortunately determining the potential cause of disorders at this stage are difficult if not impossible to determine.
The time of arrival of the pathogen to the crop/field and when symptoms occur are very important in terms of making an accurate diagnosis of a particular disorder. In addition, important features of a particular disease may not be able to be easily discerned on dead/decomposing tissues. Lastly, senesced plants are prone to secondary infection by microbes and therefore it is likely that something can be isolated or observed late in the growing season. Thus the importance of regular scouting of fields. Scouting allows the producer to address issues 1) quickly, 2) in a timely fashion, and 3) preventatively (helping to determine what to do next season). Growers should plan on regular scouting of fields throughout the growing season to avoid these potential issues that can occur “out of the blue.”