Causal Agent:
Cucumber Mosaic Virus (CMV), many strains are known.

Distribution:
Worldwide

Symptoms:
All cucurbits are susceptible, though the disease rarely affects watermelon. Symptoms first appear on younger leaves which curl downward and become mottled, distorted, wrinkled and reduced in size. The plant is stunted as internodes become shorter, resulting in a rosette of the youngest leaves. Fruit are often misshapen, mottled, warty and reduced in size. Infected fruit may look like a "white pickle" in which there is very little green color. If a plant becomes infected after midseason, vine growth may not be reduced, but developing fruit may be bumpy and deformed.

Conditions for Disease Development:
Cucumber mosaic virus has an extensive host range that allows it to survive on weeds, ornamentals and other crops. The virus is transmitted mainly by aphids. In multiple harvest operations pickers may serve to spread the virus from one plant to another.

Control:
Use resistant varieties. Avoid planting near infected perennial flowers or susceptible neighboring crops. Eliminate perennial weed hosts. Control insects with an effective insecticide program.