Dan Egel, Vegetable Pathologist, SWPAC, Botany & Plant Pathology, Purdue University
The two tomato plants shown here are both healthy. However, to some observers, the leaf roll of the tomato plant on the left might seem to indicate a problem. Physiological leaf roll, as this condition is called, can be caused by stresses such as heat and drought. Since physiological leaf roll rarely results in yield loss it usually is not considered an important problem.
Look again at the tomato plants in the photo. The two tomato plants shown here are actually two different varieties. The tomato plant on the left, Mountain Spring, almost always shows some leaf roll, and is genetically more likely to show leaf roll than the plant on the right, Red Deuce. Yet, there is no indication that there is anything wrong with the Mountain Spring plant-it just shows more leaf roll.
Which plant will end up yielding more? These plants are part of an experiment in the high tunnels at the Southwest Purdue Agriculture Center in Vincennes, IN. One of the questions we hope to answer is which variety yields more in a high tunnel.