Tomato Disorders Gray Wall (Blotchy Ripening) Found worldwide Symptoms Conditions for Disease Development Affected green fruit have large patches of hard, grayish or yellowish tissue. The affected fruit appears to be poorly ripened or to have ripened at an uneven rate with some patches remaining gray or turning yellow. The cause is unknown. An association between graywall and low potassium, low boron, or high nitrogen levels has been established. The disorder is also more prevalent when temperatures are very high with low light levels, and is less prevalent during sunny, mild conditions. Inside the fruit, there is uneven coloration of tissue with some areas having a brown color. Some blotchy ripening symptoms are similar to those caused by tomato mosaic virus (ToMV) on fruit. To distinguish the disorders, ToMV causes mottling and distortion of foliage, but graywall will not affect foliage. World Vegetable Center Control There are differences in susceptibility among redskinned varieties. Follow a balanced fertilizer program. How to Identify Graywall Fruit is uneven in color, both inside and outside, with hardened patches of grayish or yellowish tissue. AVRDC Publication 04-602 Written by Ray Cerkauskas, Visiting Scientist from Agriculture and Agri-Food Canada. Edited by Tom Kalb. Revised August 2005. Published by AVRDC – The World Vegetable Center; P.O. Box 42, Shanhua; Taiwan 741; ROC. tel: (886-6) 583-7801; fax: (886-6) 583-0009; email: avrdcbox@avrdc.org; web: www.avrdc.org
