POSSIBLE CAUSES OF PERIWINKLE PROBLEMS
- Watering (over/under).
- Vinca Wilt (Sprioplasma citri) causes mosaic, yellowing and stunting of some plants and sudden permanent wilting of others. Stems and roots appear normal. This disease is thought to be spread by the beet leafhopper, a notorious carrier of plant viruses.
- Rhizoctonia can cause the wilting death of periwinkles also, but typically rots the stems at ground surface. This fungus disease is common to local flower beds all year round, and periwinkle is one plant that is highly susceptible.
- Thielaviopsis basicola is a fungus that lives in the soil and attacks the roots through a wound or even nematode damage. Ideal conditions for the disease include cold, damp soils with the pH being near neutral. Periwinkle is susceptible to this fungus disease.
Remove and discard infected plants. Do not replant periwinkle in same area.