Thursday, July 16, 2015

Cucumber Mosaic Virus on Vegetable Plants

Curled and deformed pepper leaves at the terminal of a branch
CMV on chile pepper (Photo: NMSU-PDC)
Deformed tomato plant infected with virus
CMV on tomato (Photo: NMSU-PDC)
Featured Diagnosis - Cucumber Mosaic Virus. Are some of your vegetable plants deformed, twisted or elongated? Are the leaves mottled, wrinkled or curled? Are the plants stunted and not producing any fruit? If you answered yes to any of these questions, then your plants may be suffering from Cucumber Mosaic Virus (CMV). This is a common virus, worldwide, and is present every year in New Mexico. CMV can cause a wide range of symptoms depending on host, age of the plant, virus strain and environmental conditions. The disease is sometimes referred to as “shoestringing” because of the effect on young leaves to develop a narrow, elongated, tendril‐like appearance. Although common, this symptom is not always associated with infection. Other common symptoms include deformity, wrinkling, twisting, curling, yellowing (chlorosis), and mosaic or mottling.

Unfortunately, CMV doesn’t produce unique symptoms and diagnosis based solely on visual observations is risky. Many other viruses produce similar symptoms. Likewise, some herbicides may cause look-a-like damage. Whether or not there has been an herbicide application on or near affected plants is an important consideration in distinguishing between a virus disease and herbicide damage. The number of plants affected may also be a clue to the cause. Typically, a virus will affect a relatively small number of plants whereas herbicide injury may be more wide-spread. A laboratory test can confirm infection by CMV and/or other plant viruses.

A composite photo of two tomato leaves infected with virus. The leaf on the left is curled and the leaf on the right is yellow and misshaped.
Leaf symptoms of CMV on eggplant (left) and tomato (right)
(Photos: NMSU-PDC)

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