Tobacco rattle virus

TRV has a global distribution, affecting plants in many regions worldwide. It is found in parts of Africa (e.g., Egypt, South Africa, Tunisia), the Americas (e.g., Brazil, Canada, Cuba, United States), and Europe. In the United States, TRV is present in several states, including California, Colorado, Florida, Idaho, Michigan, Minnesota, North Dakota, Oregon, Washington and Wisconsin.

Biology

TRV is primarily transmitted by stubby-root nematodes (genera Trichodorus and Paratrichodorus) that feed on plant roots, but it can also spread through infected plant material and contaminated tools. Infected plants may exhibit symptoms such as mottling, ringspots and necrosis, with potatoes specifically developing corky ringspot disease. Structurally, TRV is a rod-shaped virus with a bipartite RNA genome, consisting of two separate RNA molecules.

Symptoms

TRV symptoms vary by plant but commonly include mottling, ringspots, chlorotic spots and necrotic lesions on leaves. Infected plants may also show leaf deformities. In potatoes, TRV causes corky ringspot disease, characterized by necrotic, corky spots, arcs, or rings in the tuber tissue. Symptoms can range from mild to severe, depending on the host plant and environmental conditions.

Damage

Symptoms caused by TRV lead to unmarketable tubers and substantial economic losses for potato growers

Management

Managing TRV involves controlling stubby-root nematodes through soil fumigation and crop rotation, using virus-free seeds, practicing strict sanitation protocols, and controlling weeds that can act as virus reservoirs. Regular monitoring of soil by qPCR testing and plants for nematodes and TRV symptoms is also crucial. Avoiding planting sensitive cultivars in infested fields and abandoning highly infested fields can further reduce the virus’s impact. Implementing these integrated practices helps minimize TRV’s spread and damage.

Further reading

• Management of corky ringspot disease of potatoes in the Pacific Northwest, CIS 1162
• TRV in potatoes: Corky ringspot disease and management practices
• Compendium of potato diseases, 2nd edition

Pesticide warning

Always read and follow the instructions printed on the pesticide label. The pesticide recommendations in this University of Idaho webpage do not substitute for instructions on the label. Pesticide laws and labels change frequently and may have changed since this publication was written. Some pesticides may have been withdrawn or had certain uses prohibited. Use pesticides with care. Do not use a pesticide unless the specific plant, animal or other application site is specifically listed on the label. Store pesticides in their original containers and keep them out of the reach of children, pets and livestock.

Trade names — To simplify information, trade names have been used. No endorsement of named products is intended nor is criticism implied of similar products not mentioned.

Groundwater — To protect groundwater, when there is a choice of pesticides, the applicator should use the product least likely to leach.