Tobacco Rattle Virus (TRV)

Need to know

• Tobacco Rattle Virus (TRV) is a plant pathogenic virus to many plants such as ornamental flowers, tulips, petunias, potatoes, and many others.
• Symptoms on leaves can vary from ring spots to a wavy line, mosaic or mottled patterns.
• Infected rootstock is the most common way this disease moves long distances, and it can also spread by mechanical transmission. 
• Focus on prevention. Unfortunately, there is no treatment once a plant is infected.

Overview

Tobacco Rattle Virus (TRV) is a plant pathogenic virus to many plants such as ornamental flowers, tobacco, potatoes, and many others (see host range table at the end of the article). While this virus has a wide host range, it also causes various symptoms depending on the host. Some plants may have no symptoms, while others may be stunted and have foliar symptoms, including mottling, discolored ring spots, or wavy line patterns.

Symptoms

Symptoms on leaves can vary from ring spots (Ringspot Pattern) to a wavy line pattern (Line Pattern) to a mosaic (Mosaic Pattern) or mottled pattern. There can also be no symptoms at all or only on the part of the plant. The leaf discoloration is typically more evident during cooler months and will dissipate during the warmer months of the growing season. This disease does not typically stunt peonies or cause problems with flowering. 

Signs

No evidence of the pathogen will be visible with the naked eye. Specialized testing is required to confirm this and other diseases caused by this virus.

 

Disease Cycle

Infected rootstock is the most common way this disease moves long distances. TRV spreads from plant to plant by using dirty pruning tools, known as mechanical transmission, which has been proven experimentally, but its role in nature is unknown. Various species of root nematodes are known vectors of this disease. These nematodes become infected by feeding on an infected plant. When the nematode moves to another plant to feed, the virus is transmitted to a healthy plant. After infection, the plant may begin to show symptoms or remain symptomless depending on weather conditions. The nematode spread of this virus is favored by high moisture soil, where nematodes can move and have better access to roots.

 

Samples Needed for Diagnosis and Confirmation

The Iowa State University Plant & Insect Diagnostic Clinic can help you to investigate and confirm if your plant has this disease. Please see our website for current forms, fees, and instructions on collecting and packing samples. 

We can test asymptomatic and symptomatic leaves (5- 10) with a DNA-based method; make sure to select the additional testing box in the submission form.

If your sample is from outside of Iowa please do not submit it to the Plant & Insect Diagnostic Clinic without contacting us. Contact information for each state's diagnostic laboratory for U.S. residents.

Management

• Focus on prevention. Unfortunately, there is no treatment once a plant is infected.
• Be vigilant;  inspect new plants for symptoms before purchasing and planting. Scout for early symptoms throughout the growing season.
• Avoid planting susceptible plants where there have been problems with TRV or nematodes in the past.
• When replanting on an infected area, avoid susceptible plants (list above) and select plants that are not susceptible to TRV.
• Pruning out symptomatic leaves showing symptoms will not help as the entire plant is infected even if the whole plant is not showing symptoms.
• If there are symptoms on a plant, pruning tools used on the infected plant should be cleaned before using the tools on other plants.
• Lastly, the plant can be removed and destroyed to try to prevent other plants from being infected.
• While this may help, it may not stop the spread as nearby plants may already be infected but symptomless.
• No chemical treatments are available or recommended for TRV.

 

Host Range

While this virus has a wide host range (~400,  most important ones listed below),  it can cause various symptoms depending on the host.

Annuals	Perennials	Weeds
Barley	Aster	Beggarticks
Bean	Bleeding hearts (Dicentra spp)	Broadleaf plantain
Beets	Gladiolus	Buckwheat
Brassicas (cole crops: Cabbage, Kale, broccoli, etc )	Iris	Cocklebur
Calendula	Peony	common chickweed
Cockle bur	Tulips	Creeping buttercup
Corn	Allium spp	Green foxtail
Cucumber	Blackcurrant (Ribes nigrum)	Hairy nightshade
Faba beans	Coral Bells (Heucheras)	Henbit
Marigold	Creeping Jenny (Lysimachia nummularia)	Lambsquarters
Oats	Daffodil (Narcissus spp.)	Pigweed
Onion	Epimedium	Purslane
Peas	Hyacinth	Shepherd’s purse
Pepper	Hydrangea arboescens	Sowthistle
Petunia	Hydrangea macrophylla
Potato	Lady slipper (Cypripedium renigae)
Rye	Lopseed (Phryma leptostachya)
Spinach	Petunia X hybrida
Sunflower	Sedum
Tobacco (Nicotiana tabacum)
Vinca
Wheat

 

Fungicide applications may be avoided by following good Integrated Pest Management practices like those listed in this encyclopedia article. Often, only preventative application is effective to manage plant diseases. If the problem requires a fungicide, state law requires the user to read and follow all labels accordingly. For more information, read Proper fungicide use.