Gray Wall or blotchy ripening is a disorder that affects ripe tomato plants that has no real known cause. Gray Wall is a condition that leaves otherwise ripe tomatoes with patches of grayish or yellowish tissue along the outside and inside of the fruit. According to The World Vegetable Center, a correlation between low potassium, low boron, or high nitrogen levels and Gray Wall have been established. In this article, we will examine the possible causes, symptoms and control for Gray Wall in tomato plants.
Possible Causes of Gray Wall
Although the actual cause of the tomato disorder is unknown, possible causes of Gray Wall have been associated with fertilizer imbalances, bacteria and environmental conditions. The low and high nutrient levels as mentioned previously are associated with improper fertilization. For instance, nitrogen and potassium are primary macronutrients that are found in all fertilizer and have a variety of problems associated with improper levels during initial fertilization. According to Penn State College of Agricultural Sciences, environmental conditions such as low light intensity, low temperature levels, excessive soil moisture, heavy soil compaction, high levels of nitrogen and low potassium levels are all contributing factors for Gray Wall.
Symptoms of Gray Wall
Symptoms of Gray Wall are easily noticed on the developed tomato fruits late during the growing season. Patches of grayish or yellowish tissue hardens on the outside and inside of the ripened fruit. The patches look similar to a tomato that has not been fully ripened and can affect substantial or minor portions of the fruit. According to The World Vegetable Center, Gray Wall symptoms are similar to that of the tomato mosaic virus. The main difference between the two disorders are that the tomato mosaic virus will cause distortion of foliage and molting while Gray Wall only affects the fruit, states the World Vegetable Center.
Because the cause of Gray Wall is for the most part unknown, treatment varies on an individual level. Proper fertilization is the first line of defense for preventing Gray Wall. Soil tests are used to determine how much fertilizer to apply for the proper growth of tomatoes. University or private-based labs test soil nutrient levels for a nominal fee, which helps determine the right amount of fertilizer to apply. Low light levels are one variable that has a positive correlation associated with Gray Wall, which means you will want to make sure that the tomatoes get plenty of sun.
Personal experience studying agricultural economics