Tomato Spotted Wilt Virus (TSWV)
This virus disease shows up occasionally in landscape plantings
of vinca and many other herbaceous plants. TSWV is spread by tiny insects
called thrips. Symptoms vary from host to host. On vinca, symptoms include
black concentric ring spots or line patterns, yellowing, stunting and
Inspect plants for virus symptoms prior to purchase. Remove all
diseased plants from flower beds, as infected plants cannot be cured and can
support spread of the disease. Thrips management hasn`t been shown to
significantly slow the spread of TSWV. In addition, thrips are difficult to
control because they often feed deep within flowers or flower buds, and two
life stages, the eggs and the pupae, are unaffected by insecticides. Avoid
planting vinca near vegetable gardens, as many vegetables are also susceptible.
Controlling weeds is also essential because many weeds can harbor both thrips
and the virus.