How to Manage Pests

UC Pest Management Guidelines


Cucumber Mosaic

Pathogen: Cucumber mosaic virus (CMV)

(Reviewed 12/09, updated 12/09)

In this Guideline:


The first symptom of cucumber mosaic is a clearing of veins, followed by development of mosaic patterns or mottling consisting of irregularly shaped, dark green areas alternating with light green or yellow areas. Leaves on some species and cultivars are drastically reduced in size and growth is often retarded. Malformations of the fruit can also occur.


Cucumber mosaic virus has a very wide host range including cucurbits (except watermelon), tomato, spinach, celery, safflower, beans, blackeyes, peppers, beets, potatoes, many ornamentals and weeds. The virus is transmitted by many species of aphids and could be seedborne.


The occurrence of this virus is erratic and unpredictable; consequently, control of this disease is not attempted. In studies, silver reflective plastic mulches applied at planting have been shown to be effective in repelling aphids from plants, thereby reducing or delaying virus infection. Mulches help plants off to a healthy start and are effective until expanding foliage covers the reflective surface. Mulches may need to be removed in the desert areas when summer temperatures are excessive for optimal growth of plants. However, in the Central Valley and cooler areas, mulches have not caused plant damage in the summer; in fact, they improve soil moisture and nutrient retention, which may further aid plant productivity.


[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Cucurbits
UC ANR Publication 3445


R. M. Davis, Plant Pathology, UC Davis
T. A. Turini, UC Cooperative Extension, Imperial County
B. J. Aegerter, UC Cooperative Extension, San Joaquin County
J. J. Stapleton, UC IPM Program, Kearney Agricultural Center, Parlier

Acknowledgment for contributions to Diseases:
W. D. Gubler, Plant Pathology, UC Davis

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