Disease Lesion Mimic
July 21, 2011 by Steven Heightchew
Disease Lesion Mimic
Disease Lesion Mimic is a phenomenon that shows up occasionally from year to year somewhere in the Corn Belt. Symptoms of Lesion Mimic include interveinal striping to spotting and areas of cell death across the entire corn leaf. In some cases the symptoms may appear similar to foliar disease because they can begin on lower leaves and spread up the plant, but no pathogen has been confirmed in samples. Some may consider magnesium deficiency the culprit. However, in most cases there is no correlation to fertility levels. Mimic also tends not to favor any specific soil type in most cases.
Causes
A large class of mutations exists in corn that can cause spontaneous development of lesions varying in size, shape and color. Disease Lesion Mimic symptoms are most likely caused by the les mutant gene in the corn genome in response to some stress. In other words, specific hybrids can carry the les mutant gene and are more likely to exhibit phenotypic expressions. Environmental conditions that contribute to phenotypic expressions of the les mutant gene include intense sunlight and high temperatures, as well as wet, poorly drained soil conditions to name a few.
Symptoms
At AgriGold, it has been our experience that the symptoms revealed in figures 1-4, which all exhibit this type of interveinal striping, come from corn plants that have sat in poorly drained conditions through a key part of their life cycle. Some hybrids that sit in waterlogged, saturated soils from the V5-V9 stage can exhibit these symptoms soon afterwards. Hybrids that exhibit this type of Disease Lesion Mimic are generally those that require well drained soils to maximize yield potential. Yield losses can occur based on the stress that triggered the phenotypic response. In this case, water logged, saturated conditions creates the stress.
Awareness
This type of Disease Lesion Mimic has already been identified in several areas of the Corn Belt in 2011. We expect to see a fair amount of these symptoms appear particularly in areas that have been receiving an over abundance of moisture in recent weeks or days.
In an article by University of Nebraska it was stated that, in 2010, approximately 30% of samples received by UNL Plant and Pest Diagnostic Clinic had symptoms caused by the genetic mutation, Disease Lesion Mimic.
