The shamrock plant is also known as purple shamrock or the love plant. Its scientific name is Oxalis triangularis and it is a member of the Genus Oxalis. This plant has purple triangular-shaped foliage, making it an ideal choice for containers, borders or as an indoor plant. The shamrock plant is susceptible to certain diseases that can cause white spots to develop.
White spots on the shamrock plant are typically caused by two diseases. Powdery mildew is a fungal disease that causes white fungal patches to develop on the affected plant. Another disease that causes white spots is rust, which is also a fungal disease.
Shamrock plants that develop powdery mildew exhibit symptoms such as white patches of powdery fungus on stems, leaves, flowers and buds. According to Ohio State University, heavy infections cause cause entire leaves to be coated in fungi. Rust symptoms in the shamrock plant include pale yellow flecks on leaves and white powdery fungus on leaves, buds and flowers. Severe rust infections cause white spots to cover the majority of the plant.
Applying fungicides to shamrock plants may help prevent or eliminate the symptoms associated with powdery mildew and rust. Most infections remain mild and do not require treatment. Shamrock plants growing in shady, cool and humid areas are most susceptible to these fungal diseases.