Leaf Spots on Lavender

Insects

• Lavender, Lavendula, does not attract many harmful pests. The four-lined plant bug is one of the few insects that may damage lavender plants. The insect lays its eggs in the stems of the plants. Upon hatching, they begin to feed on the sap and nutrients found inside the leaves of lavender plants. The repeated feedings may create discolored spots on leaves and weaken the overall plant. Use pesticide to manage and prevent plant bugs.

Wilt

• Lavender is susceptible to multiple wilt diseases that create leaf spots and other damage. Verticillium wilt is particularly damaging to lavender plants. The wilt is spread by a soil-dwelling fungus that attacks the roots of lavender plants. Verticilium wilt generally causes leaves to wilt and turn yellow. In beginning stages, leaves may be covered with small spots as early wilting begins. Fungus grows best in wet, warm conditions. Verticilium wilt is particularly common in summer months.

Root Rot

• Fungal diseases are also responsible for root rot, which becomes problematic in moist soil. Root rot is just that, decaying roots that become weakened and die due to over-saturation. Discolored spots may appear on leaves before they begin to wilt and drop from the plant when root rot is present. Lavender plants may die if conditions are not improved.

Management

• The best way to treat lavender plant problems is to avoid them. Cover the soil around lavender plants with a 2-inch layer of white sand. The sand is inhospitable to soil-dwelling fungus and bugs that may feed on lavender plants. Healthy lavender plants are the best defense against diseases that cause leaf spots and other problems. When plants do become affected by disease, remove them immediately to prevent the fungus from spreading. Lavender needs well-drained, sunny soil for optimal cultivation and growth.