Virus Diseases of Cucurbit Crops
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Diseases caused by viruses are common on cucurbits in Kentucky, especially during warm weather and later in the season, when insect populations tend to be higher. Cucumber mosaic virus (CMV), papaya ringspot virus (PRSV), squash mosaic virus (SqMV), watermelon mosaic virus (WMV), and zucchini yellow mosaic virus (ZYMV) are among the most common viral pathogens. Symptoms include stunting, mosaic patterns on leaves, and leaf distortion; different viruses may cause similar symptoms. Aphids are the primary vectors for the major viruses that attack cucurbits in Kentucky, although SqMV is vectored by cucumber beetles. Aphid-transmitted viruses are part of a complex belonging to the Potyvirus group.
Potyvirus complex symptoms on pumpkin foliage.
(Photo: Kenny Seebold, University of Kentucky)
Potyvirus complex symptoms on pumpkin foliage.
(Photo: Kenny Seebold, University of Kentucky)
Potyvirus complex symptoms on pumpkin fruit.
(Photo: Timothy Coolong, University of Kentucky)
Potyvirus complex symptoms on zucchini squash.
(Photo: John Hartman, University of Kentucky)
Management:
- Adjusted planting date (viruses tend to be more severe in later plantings)
- Resistant varieties (primarily squash)
- Weed control (weeds can harbor vectors and viruses)
- Vector control (minimally effective)
- Reflective mulches
- Stylet oils
