Viruses:
Viruses cause mosaic patterns (light green, dark green) in leaves, puckering,
leaf distortion, stunting, shortened internodes and misshapened fruit. See
symptoms on yellow squash. Infected yellow squash and pumpkin produce fruit
with green blotches of varying degrees. It is impossible to diagnose specific
viruses based on symptoms. Often two or more viruses are detected in a single
plant. Cucurbit viruses generally overwinter in weed hosts. Avoid late season
planting and control weeds around fields. Insect control has not proven effective.
Development of resistant varieties using biotechnology techniques is underway.
Virus Transmission Host Range
Seed Vector
Papaya ringspot no aphid only cucurbits
Watermelon Mosaic no aphid wide
Cucumber Mosaic * yes aphid wide
Zucchini Yellow Mosaic no aphid wide
Squash Mosaic* yes beetle limited
Tobacco Ringspot yes nematode wide
(Xiphinema)
thrips, beetles,
other
Squash leaf curl ** no whitefly limited
