Causal Agent:
Zucchini Yellow Mosaic Virus (ZYMV).

Distribution:
North America, Europe, Asia and the Middle East.

Symptoms:
All cucurbits are susceptible. Infected leaves are yellow with severe mosaic symptoms and a blistered or tendril-like appearance. Fruit are bumpy, distorted and malformed. Growth of infected plants is greatly reduced.

Conditions for Disease Development:
The virus is transmitted by aphids. Weeds and cucurbit crops are the main source of the virus.

Control:
Weed sanitation programs should be practiced to reduce sources of the virus. Controlling aphids is especially important early in the season. Mineral oil sprays and reflective mulches may be effective during early plant growth in avoiding infection.