tomato brown rugose fruit virus - onfloriculture
TRANSCRIPT
Agriculture, Food and Rural Affairs
Tomato Brown Rugose Fruit Virus
Cara McCreary
Greenhouse Vegetable IPM Specialist, OMAFRA
AGENDA
• What is a virus?
• What is ToBRFV?
• Background
• Symptoms
• Transmission
• Diagnostics
• Crop protection
What is a Virus?Smaller than a single cell
Signs:NONE
Symptoms:Quite variableStunting or distorted growthLeaf and fruit spots often in rings
Virus Characteristics
• Too small to be seen with a light microscope
• Only visible using electron microscope
• Multiply only in living cells
• All are obligate parasites • cannot replicate without exploiting a suitable
host • without host, will fail to replicate but can
survive away from main host in tissue and some survive on other surfaces such as wood, plastic or metal
• Enter the plant through wounds, broken hairs, or vectors (insect, fungus or nematode)
Transmission of Plant Viruses
Mechanical: sap on tools, hands, clothes, animals
• e.g. tobacco and tomato mosaic virus (TMV/ToMV), Pepper mild mottle mosaic virus (PMMoV), Pepino mosaic virus (PepMV), Cucumber green mottle mosaic virus (CGMMV)
Seed: borne inside seed or transmissible through seed coat
• e.g. ToMV, pepper mild mottle mosaic virus, CGMMV
Fungus: in greenhouse, often soil-borne fungus
• e.g. MNSV or CNSV by Olpidium, in cucumbers
Transmission of Plant Viruses
Insects: many common pests of greenhouse vegetables• Aphids – cucumber mosaic virus (CMV), zucchini yellow
mosaic virus (ZYMV)
• Cucumber beetles & aphids – cucumber mosaic virus (CMV)
• Thrips – tomato spotted wilt virus (TSWV) & impatiens necrotic spot virus (INSV)
• Whitefly – beet pseudo yellow virus (BPYV), tomato chlorosis virus (TOC)
Nematodes: usually soil-dwelling plant pathogenic nematodes• e.g. tobacco ringspot virus
What is Tomato Brown Rugose Fruit Virus?(ToBRFV)
Family: Virgaviridae
Genus: Tobamovirus
• Like TMV (Tobacco Mosaic Virus), ToMV (Tomato Mosaic Virus)
Characteristics of Tobamovirusgenus:
• Very persistent in the environment
• Highly transmissible and easily spread mechanically
• Virulent strains can be very damaging to host crops
DeRuiter
What sets ToBRFV apart?
Tomato Resistance
• Able to overcome all known genetic resistances including the Tm-2² gene
• May result in severe fruit symptoms on cultivars resistant to TMV and/or ToMV
Pepper Resistance
• Does not seem to overcome the L genes (for resistance to TMV and PMMoV) DeRuiter
DeRuiter
American Seed Trade Association (ASTA) QA
Objectives:
1. How to detect the virus
2. Its detrimental impact
3. Prevention and mitigation
https://www.betterseed.org/wp-content/uploads/ToBRFV-QA.pdf
Tomato Brown Rugose Fruit Virus (ToBRFV)
DeRuiter
What crops are affected?
• Tomato and pepper are main hosts
• Several Nicotiana spp. (including tobacco) develop symptoms
• Some weeds, Petunias and other ornamentals may act as reservoirs
• Eggplant and potato did not show symptoms after inoculation in one study; however, recent reports from Mexico of infected eggplant
Note: weed and ornamental hosts may be source of inoculation
Tomato Brown Rugose Fruit Virus (ToBRFV)
Photos: DeRuiter
Symptoms - TomatoesFoliar:
• Chlorosis, fern leaf, mosaic and mottling, leaf narrowing
Calyx:
• Browning of the veins or necrosis at the tips
Fruit:
• Blotchy, pale, yellow or brown necrotic spots
• May be undersized, deformed, irregular maturation, fewer fruit, or complete abortion
Damage estimates:
10-15% symptomatic fruit – 100%
Photo: DeRuiter
Symptoms of ToBRFV
“Note that it has been reported that some tomato
varieties can develop a high virus level without
physically expressing symptoms.
Infected plants of these varieties can then
unwittingly become a source for spread of ToBRFV
infection to healthy tomato or susceptible pepper
plants.” (ASTA)
Tomatoes
DeRuiter
Symptoms - Peppers
Foliar:
• deformation, yellowing and mosaic
Fruit:
• deformed, yellowing or brown necrotic areas or green stripes
Damage estimates:
• None available
May 8, 201913
Photos: DeRuiter
How is ToBRFV transmitted?
1. Mechanically.
• Through contact: people, hands, tools, clothing, chewing insects, birds, bees, grafting, roots, seeds, etc.
• May be spread by bumble bees or other insects,(as are many other viruses)
2. Seed transmitted.
• Primarily on seed surface, and to lesser extent internally
• Can maintain infectivity for weeks to years
• Transmission from seed to seedling may be low; however, contact with infected material can spread the virus rapidly between plants, ranges, fields, etc.
How can you protect your crops?
• Use certified seed - GSPP
• Practice strict sanitation at all stages of crop production
• All workers and visitors should practice strict hygiene
• Thorough handwashing
• Freshly laundered uniforms or clothes
• Footwear that remains on farm
• Be mindful of people moving from farm to farm
• Use disposable lab coats, gloves (followed by disinfectants) if handling plants
• Do not visit more than 1 operation of the same crop in the same day
• Go home and shower!
Prevention is key
How can you protect your crops?
• Conduct a thorough cleanout between crops
• Manage imports
• Practice clean breaks rather than cutting where possible
• Disinfect:• Use footbaths, tire baths, hand sanitizer (refresh
disinfectants regularly)• Equipment, vehicles, carts, tools, etc. regularly• Irrigation water
• Ensure ALL workers and visitors follow biosecurity protocol
May 8, 201916
May 8, 201917
How can you protect your crops?
CFIA’s Plant Health Biosecurity Guide
http://www.inspection.gc.ca/plants/plant-pests-invasive-species/biosecurity/guide/eng/1323477130171/1323477259986
OGVG’s Visitor Biosecurity Handout
https://www.hortcouncil.ca/wp-content/uploads/2019/04/Visitor-Biosecurity-Handout-EN.pdf
CFIA’s Greenhouse Vegetable Sector Biosecurity Guide
http://www.inspection.gc.ca/plants/plant-pests-invasive-species/biosecurity/greenhouse-vegetable-sector-biosecurity-guide/eng/1484722296145/1484722331070
Biosecurity is your friend
What if you suspect you have it?
Properly identify by sending to Canadian diagnostics lab
The 3 R’s of virus management:
• Restrict access, block off rows
• Promptly remove infected plants – place in sturdy garbage bags and send to landfill
• Rotate crops if possible (the longer the rotation, the better)
May 8, 201919
Photos: DeRuiter
Steps to managing a virus
Step 1: Practice strict biosecurity
Step 2: Quarantine known or suspected plants
Step 3: Properly diagnose
Step 4: Remove infected plants
Step 5: Clean and disinfect regularly
Step 6: Monitor diligently
Step 7: Conduct a thorough clean out between crops
Step 1: PRACTICE STRICT BIOSECURITY
Step 1: PRACTICE STRICT BIOSECURITY
Step 1: PRACTICE STRICT BIOSECURITY
Step 1: PRACTICE STRICT BIOSECURITY
Perhaps MOSTimportantly…
Don’t have fancy boot disinfection equipment?
Here’s what you’ll need:
• Water
• Soap
• Scrub brush
• Disinfectant
• Buckets (optional)
• Spray bottle (optional)
No problem. You can easily clean and disinfect work boots with some basic equipment.
Scrub to remove debris and dirt, rinse before proceeding.
26
Dissolve disinfectant and submerge boots and/or spray boots directly with disinfectant.
Step 2: QUARANTINE KNOWN OR SUSPECTED PLANTS
• Assume it is
• Flag the plant
• Restrict access IMMEDIATELY
• Designate equipment and workers to that area
• Manage workflow in infected area:
• Work in one direction• Work in infected area
last
Step 3: PROPERLY DIAGNOSE
HOW?
• Immunostrips
• Send to diagnostics lab in Canada
• Conventional, end point reverse transcription PCR (developed by Ling et al., USDA)
• Followed by sequencing
WHY?
• What disease is it?
• How is it transmitted?
• How can you prevent it from spreading?
Step 4: REMOVE INFECTED PLANT(S)
• Remove infected plant(s) IMMEDIATELY.
• Depending on how the virus is transmitted, may need to remove a number of plants surrounding the infected plant(s).
• Properly dispose of ALL plant material.
How to dispose of infected plants
Follow ALL biosecurity protocol to prevent further spread of infection. This includes wearing protective gear and frequent disinfection of footwear.
31
Cut the infected plant free from its support and disinfect scissors.
Cut block free from the slab and disinfect knife.
With help, carefully place the infected plant inside a sturdy garbage bag, keeping the garbage bag’s
exterior clean and seal the bag.
What not to do…
Step 5: CLEAN AND DISINFECT REGULARLY
• Regularly clean and disinfect tools, equipment, pathways, especially in or near an infected area.
• Remember: anything that has plant sap/residue on it, could be a source of inoculum. Focus on high risk areas.
• MUST remove organic matter PRIOR to disinfecting
36 Presentation Name
Step 5: CLEAN AND DISINFECT REGULARLY
• Picking crates…• Hard plastic
• Microbreaks are a great place for viruses to hide
Photo credit: https://groups.google.com/forum/#!topic/greenhouse-marketing-forum/jo5j3ztshsQ
Step 5: CLEAN AND DISINFECT REGULARLY
• Think about what hands touch AFTER they touch plants.
• e.g. bathroom door knobs, keyboards, mouse, lunch table, etc.
Is pasteurization an option?
Temperatures for Killing Some Organisms
Pest Temp (0C) Time (min)
Bacteria 60 10
Botrytis 55 5
Pythium 46 40
Insects & mites 60-71 20
Weeds 70-80 15
Temperatures at which certain viruses lose infectivity after exposure for minimum of 10 min
Pepino Mosaic Virus 65-700C
Tomato Spotted Wilt Virus 450C
Cucumber Mosaic Virus 700C
Melon Necrotic Spot Virus 600C
Zucchini Yellow Mosaic 600C
Cucumber Necrosis Virus 75-800C
Tobacco Etch Virus 550C
Tobacco mosaic virus > 900C
Cuc green mottle MV 90-1000C
But this is so overwhelming…
• Tools
• Scissor carts
• Picking crates
• Pallets
• Packing lines
• Door handles
• Fork lifts (especially forks)
• Walkways
• Irrigation equipment (incl. nutrient solutions, drip lines, etc.)
• Vehicles
• Tractors
• Sprayers
• Other hand tools
Regularly CLEAN and disinfect surfaces with heavy traffic and contact with plants or people, including:
Dr. Oualid Ellouz, 2017
Step 6: MONITOR DILIGENTLY
• Continue scouting, focusing on expected patterns based on what’s known about virus transmission.
• For example:
• Mechanically transmitted viruses tend to spread in the same direction as workers, focus on these areas.
• For insect transmitted viruses, monitor and manage insect populations.
• If more infected plants are found, return to step 2
Step 7: CONDUCT A THOROUGH CLEAN OUT BETWEEN CROPS
• Properly dispose of old crop
• Maintain warmer temperatures
• Remove all organic matter
• Clean irrigation system
• Clean, rinse and disinfect equipment
• Clean, rinse and disinfect structure
"None of the actors (seed companies, nursery gardeners, producers, distributors)
can avoid implementing all preventive containment measures: if only one link of
the chain fails, it risks putting the entire Sicilian tomato production at risk.”
Quote from the Mar 11 Hortidaily
It is a “community pest”
Next steps
“Seed companies are diligently working on identifying and introducing resistance to the virus
in new varieties. However, it could take several years until new resistant varieties are introduced”
(ASTA)
Future research
• Attenuated virus
• Disinfectants
Take Home Messages
Biosecurity is your first line of defense
• Focus on riskiest pathways first
• Think: Sanitation, Disinfection, Hygiene
Establish a support network
• Government
• Grower organizations
• IPM specialists, suppliers, consultants
• Supply chain
BE EMPOWERED!
