Tomato Spotted Wilt Virus


TSWV Foliar SymptomsTSWV Foliar Symptoms

TSWV Fruit SymptomsTSWV Fruit Symptoms

TSWV Symptoms on potatoTSWV Symptoms on potato

TSWV symptoms on lettuceTSWV symptoms on lettuce


  • Tomato
  • Pepper
  • Eggplant
  • Several other vegetable and weed hosts


Tomato Spotted Wilt Virus (TSWV) is a Tospovirus spread by thrips species. It is a concern throughout the growing season.

  • Infection occurs when thrips carrying the virus feed on a healthy plant.
  • Overwinters in winter weed species and thrips.


Symptoms of TSWV vary between plant species and within a species depending on the strain of the virus, time of infection, and plant variety. Infected plants are commonly stunted (generally more severe when young plants are infected). Leaves have necrotic spots, fruit may form necrotic rings, and seeds may become discolored (although TSWV is not seed transmitted). Mature fruit has calico patterns.


This virus is occasional in Utah tomato production but is becoming more widespread. Once a plant is infected there is no cure, and if thrips are reproducing on the plant, it can serve as an inoculum source for neighboring plants. The virus is more likely to occur in fields that have had it in the past.

  • Watch for symptoms throughout the growing season.
  • Monitor thrips activity throughout the growing season.
  • Monitor fields that had the virus in the past.
  • Control thrips.
  • Remove and destroy infected plants.
  • Purchase healthy transplants.
  • Use resistant varieties.
  • Control weeds.

There are no chemical controls for TSWV

Precautionary Statement: Utah State University and its employees are not responsible for the use, misuse, or damage caused by application or misapplication of products or information mentioned in this document. All pesticides are labeled with ingredients, instructions, and risks, and not all are registered for edible crops. “Restricted use” pesticides may only be applied by a licensed applicator. The pesticide applicator is legally responsible for proper use. USU makes no endorsement of the products listed in this publication.