Tomato Spotted Wilt Virus: TSWV in Vegetable Crops: Tospoviruses

Tospoviruses In Solanaceae and Other Crops in The Coastal Plain of Georgia

Symptomatology TSWV
(Tobacco)

Alex Csinos, Natalia Martinez

TSWV can cause symptoms at all stages of growth, from transplant to maturity. However, on tobacco younger actively growing plants appear to be more susceptible to infection than slow growing hardened off plants.

The symptoms vary greatly on individual plant species and among virus hosts. Symptoms on tobacco range from discrete individual spots to systemic necrosis. Often individual discrete spots are local infections, while infections that become systemic, move from the point of initial infection to the root systems, where the virus reproduces. Systemic infection often occurs when an environmental factor triggers sudden growth of the plant, such as a temperature change, irrigation or rainfall. Systemic infection results in specific leaves and the apical bud becoming necrotic. This systemic infection often times is unilateral, indicating that it may be moving up in the xylem. Plants having ring spot symptoms on stems in absence of any foliar systems may occur late in the season. Very young, freshly transplanted tobacco may collapse and die without distinct symptoms. Note the many variances of TSWV symptom expression:

• High degree of variability
• Large foliar spots observed early in the season
• Variable symptoms
• Typical systemic vein necrosis
• Necrotic spots in flowers (guessed at file)
• Necrotic lesion in stem
• Crown and root stem necrosis
• TSWV mild isolates

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