Quick Guide to Cucurbit Viruses in the US

Numerous viruses that impact cucurbit production or for which cucurbits are a primary host have been identified in one or more cucurbit-producing regions of the United States. Some of these viruses have been present for decades while others have only recently been introduced, and some are yearly production concerns while others have not been detected in years (historic) or are under official control in the United States (transient). These viruses, outlined below according to mode of transmission and genus, are primarily transmitted by various insect vectors. In some cases, the mode(s) of transmission have not yet been identified. Virus prevalence and impact varies by region and is influenced by crop, reservoir host, and vector presence and prevalence. Virus identification by symptoms alone is not possible due to symptom similarity and mixed infections. Contact your local Extension office or diagnostic laboratory for assistance with disease and virus diagnosis. 

Insect

Whiteflies

Vector: Sweetpotato whitefly (Bemisia tabaci)

Begomovirus
Crinivirus
Ipomovirus

Vector: Greenhouse whitefly (Trialeurodes vaporariorum)

Crinivirus
  • Beet pseudoyellows virus (BPYV)

Aphids

Vectors: Multiple aphid species, including melon (cotton) aphid (Aphis gossypii) and green peach aphid (Myzus persicae)

Cucumovirus
  • Cucumber mosaic virus (CMV)
Polerovirus
  • Cucurbit aphid-borne yellows virus (CABYV)
Potyvirus
  • Papaya ringspot virus (PRSV)
  • Watermelon mosaic virus (WMV)
  • Zucchini tigré mosaic virus (ZTMV)
  • Zucchini yellow mosaic virus (ZYMV)

Beetles

Vectors: Cucumber beetles, including the spotted cucumber beetle (Diabrotica undecimpunctata howardi) and striped cucumber beetle (Acalymma vittatum)

Comovirus
  • Squash mosaic virus (SqMV)

Beet Leafhopper

Vector: Beet leafhopper, Neoaliturus tenellus (formerly Circulifer tenellus)

Curtovirus
  • Beet curly top virus (BCTV)

Thrips ( + Pollen)

Vector: Multiple thrips species

Ilavirus
  • Tobacco streak virus (TSV)

Seed

Carmovirus
  • Melon necrotic spot virus (MNSV)
Coquvirus
Comovirus
  • Squash mosaic virus (SqMV)
Potyvirus
  • Zucchini yellow mosaic virus (ZYMV)
Tobamovirus

Mechanical

Comovirus
  • Squash mosaic virus (SqMV)
Cucumovirus
  • Cucumber mosaic virus (CMV)
Ipomovirus
Potyvirus
  • Papaya ringspot virus (PRSV)
  • Watermelon mosaic virus (WMV)
  • Zucchini tigré mosaic virus (ZTMV)
  • Zucchini yellow mosaic virus (ZYMV)
Tobamovirus

Nematode

Vector: Dagger nematode (Xiphinema americanum)

Nepovirus
  • Tobacco ringspot virus (TRSV)
  • Tomato ringspot virus (ToRSV)

Fungus

Vector: Leiolpidium bornovanum (formerly Olpidium bornovanus)

Carmovirus
  • Melon necrotic spot virus (MNSV)

Not Identified/Confirmed

Orthotospovirus
  • Melon severe mosaic virus (MSMV) [suspected thrips vector]

EVCWG Publication 2401 (June 2025)

Author: Rebecca A. Melanson, Extension Plant Pathologist, Mississippi State University Extension. 

Acknowledgement

This is a publication of the Emerging Viruses in Cucurbits Working Group (EVCWG).

This publication may be distributed without alteration for nonprofit educational purposes provided that appropriate credit is given to the author and the EVCWG

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