Disease of the Month - Cucumber Green Mottle Mosaic Virus and Pepino Mosaic Virus

  Hort Snacks - January 2019
Download 1375K pdf file ("HortSnacks-Jan2019.pdf")PDF
     Subscribe to our free E-Newsletter, "Agri-News" (formerly RTW This Week)Agri-News
This Week
     Hort Snacks HomeHort Snacks Home
 Cucumber Green Mottle Mosaic Virus (CGMMV) | Pepino Mosaic Virus (PepMV)

Cucumber Green Mottle Mosaic Virus (CGMMV)

Causal Organism: a type of tobamovirus

Crops Affected: Cucurbits (cucumbers, melons, etc.) – greenhouse cucumbers = primary concern

Disease Cycle:

  • Highly infective, extremely stable, viral pathogen that can survive for an extended period in the greenhouse environment
  • Yields may be reduced by 25% or more
  • May be introduced via infected seed (seed-borne)
  • Easily spreads between plants through mechanical transmission
    • May also be transmitted by insect pests with chewing mouthparts)
  • Younger leaves are affected more than older ones, with viral activity reduced as leaves age
    • Leaves will have green, light-green or yellow-green spots
    • Veins may remain green
    • Young leaves may be deformed in heavy infections
  • Fruits may abort and drop off
    • Fruit size is dramatically reduced in those fruit that do not abort
  • Seed (thermal or chemotherapy) treatments may partially reduce transmission
  • Ensure that seed lots and new plants are virus-free, either through testing and monitoring
  • Monitor the crop carefully for the presence of symptomatic plants
    • Early infection is more serious than infection of an older crop
    • Remove early infected plant material to prevent further spread
  • Avoid overlapping crops
  • Discard and destroy heavily infected plants
  • Remove all plant debris and take it off-site, to avoid re-introduction
  • Treat crops with insect pests to reduce spread by insect vector
  • Clean and disinfect all greenhouse materials, including all structures, containers, tools, and equipment
    • Ensure that obscure and hard to reach surfaces are also treated (e.g. pipe tops, textured surfaces, structural members)
    • Some disinfection may be done on walkways and corridors during crop production, but cleaning and disinfection must be done between crops
  • Place disinfecting footbaths at the entrances of all production bays
  • Disinfect clothing, tools and gloves at the end of each row
Pepino Mosaic Virus (PepMV)

Causal Organism: virus

Crops Affected: tomato

Disease Cycle:
  • Highly contagious viral disease
  • Transmitted via mechanical contact between plants and contaminated tools, clothing, footwear, hands and other plants
    • Infection may also occur through contaminated leachate water
    • Spread via bumblebee pollinators is possible, but less likely than hand pollination
    • Spread may also occur via cuttings
  • May remain viable on dry material for several months
    • Clothing can be infective for up to 2 weeks
    • In cool, moist, organic debris, the virus can remain infective for an extended period
  • More readily observed in fall and winter months during low light and temperature levels
  • Plants may appear to have a stunted growing point or “head”
  • Distorted growth may be observed, which resembles herbicide injury
  • Leaves around the growing point may have dark spots, with necrotic lesions developing further down
    • Scorch-like spots may appear on lower leaves
  • Bright yellow spots may appear in some areas
  • Stems near the growing point may have brown streaks encircling the entire stem
    • Flower clusters may be affected, resulting in abortion
    • The calyx on infected fruit may be brown
    • Fruit may appear marbled (yellow-red mosaic patterns)
  • Plants may be symptomless
  • Ensure that plants and seed are disease-free
  • Sanitation and strict hygiene throughout all stages is key
    • Move from clean to infected areas, not infected to clean
    • Wear clean/disinfected cloths, gloves, boots, etc. when moving into a clean area
    • Have workers and clothing designated for specific areas of the greenhouse
    • Install foot baths at the entrance to different areas
  • Power wash and then disinfect the entire greenhouse structure between crops
    • Clean and disinfect all tools and equipment
    • Clean and disinfect or replace irrigation lines
  • Dip tools and gloved hands in undiluted skim milk or an appropriate disinfectant between handling individual plants
  • Carefully monitor new plants and developing crops, watching for symptoms
    • Mark infected areas and inform workers, visitors, etc. of appropriate steps to take to avoid spread
  • Bag and remove plant debris from the space and destroy promptly
Share via AddThis.com
For more information about the content of this document, contact Robert Spencer.
This information published to the web on December 12, 2018.