Tropicanna Plant Diseases

Problems With Fungus

• Botyris blight and canna rust are two diseases caused by fungal pathogens that attack the Tropicanna canna. Botyris blight is prevalent when conditions are humid and most often attacks the older leaves of the plant. Fuzzy gray growth on flowers, leaves and buds are a sign that the Tropicanna is infected with botyris blight. Removing the infected foliage will help halt the spread of botyris blight. Canna rust also occurs in moist and humid conditions, and results in orange or rust-colored spots to develop on the flowers, stems and foliage of the plant.

Viruses Infecting Tropicanna

• Canna yellow mottle, canna mosaic virus and canna mottle virus are the common viruses infecting Tropicanna plants. Viruses discolor the leaves of an infected plant, resulting in flecking, streaking, spotting and puckering of the foliage. There is no cure for viruses infecting the Tropicanna and the plant must be destroyed to prevent the viral disease from spreading. Because aphids and other insects spread the virus from one plant to the next, controlling the pests by spraying the plant with ready-to-use insecticidal soap reduces the possibility of viral infections to the Tropicanna plants.

Treatment for Tropicanna Diseases

• Copper fungicide controls various fungal disease affecting Tropicanna plants, such as botyris blight and canna rust. Unless otherwise stated on the label, apply the copper fungicide two weeks before the fungal disease appears or when the weather is exceptionally wet and humid. Mix 1/2 ounce in 1 gallon of water, or as directed by the label and spray the cannas with the solution. After symptoms appear, treat the infected plant by spray the foliage -- topside as well as underside -- with the fungicide every seven to 10 days until the disease subsides. Wear protective gear, including long sleeves, long pants, gloves and eyewear, when using garden chemicals.

An Ounce of Prevention

• Whenever possible, it's better to prevent plant diseases before they take hold. Fungal pathogens thrive in wet areas. This could be due to improper watering, poorly drained soil or other drainage issues. Ensuring the Tropicanna plant is not over-watered and growing in well-drained soil helps prevent fungal diseases. Also, keep the area free of weeds, debris and decaying plant matter. Debris and decaying plant matter act as a food source for pests while weeds provide the perfect hiding place for virus-spreading insects. Taking the necessary preventive measures before diseases start helps prolong the life of the Tropicanna plant.