Viola Perennial Shrub Diseases:
Symptoms-Leaves are yellowed and narrow rather than oval. An abnormally high number of shoots form.
Management-Remove infected plants. Control leafhoppers.
Symptoms-An abnormally high number of shoots form
Management-Remove infected plants.
Black Root Rot:
Symptoms-Plants are yellowed, stunted and die.
Management-Try to maintain the soil pH below 6.2 where the violets are growing. Apply iprodione + thiophanate methyl or fludioxonil.
Symptoms-Dying plants have white fungal growth on stems at the soil line. Small, golden-tan, mustard-seed sized structures dot the white growth.
Management-Remove infected plants. Keep mulch away from the base of the plants.
Symptoms-Leaves have purplish or yellowed areas.
Management-Apply chlorothalonil, mancozeb, mancozeb + zinc, copper sulfate or copper hydroxide in the spring when cool, wet weather prevails. Apply PureSpray Green to help control and prevent mildew.
Fungal Leaf Spots:
Symptoms-Small spots, on generally on lower leaves, enlarge and become dark purple to black, 1/4" or more in diameter with feathery margins. Leaves then yellow.
Symptoms-White fungal growth develops on the upper surface of leaves.
Management-Apply PureSpray Green. An all organic spray that works great for controlling powdery mildew. BUY NOW
Pythium Root Rot:
Symptoms-Plants wilt and die as lower stems and roots discolor and die.
Management-Remove infected plants. Apply mefenoxam or metalaxyl to protect healthy plants.
Rhizoctonia Stem Rot:
Symptoms-Roots and stems brown as plants wilt and die.
Management-Remove infected plants. iprodione, iprodione + thiophanate methyl, or fludioxonil to protect healthy plants.
Symptoms-Pustules yellow-orange spores form on the underside of leaves. The upper side of the spot is yellow.
Management-Avoid overhead irrigation. Apply myclobutanil or chlorothalonil.
Symptoms-White spots with purple edges form slightly swollen areas along petioles and leaf veins.
Management-Apply thiophanate methyl, chlorthalonil, mancozeb, or chlorthalonil + thiophanate methyl to protect leaves not yet infected.