Petunia Diseases

Types

• Petunias can develop diseases related to severely deficient soils or those caused by insects, fungi or viruses. Among the diseases related to poor soil are stunted growth and yellow spots. Viral diseases include impatiens necrotic spot virus, while fungal conditions include damping-off. Insect infestations are most commonly cutworms or aphids.

Symptoms

• Symptoms of disease in petunias depend on the condition, but different diseases can cause similar issues. Wilting can be a sign of damping-off, crown rot or of aphid infestation. Yellow spots can be caused by soil with low iron content, while slightly darker or open spots can result from botrytis blight. Careful examination while consulting an illustrated encyclopedia of plant diseases is often needed to determine the problem.

Treating Diseases

• Although the specific diseases vary, most petunia diseases have common cures. All mold problems require reducing moisture around the plant, as well as application of a natural fungicide, such as tea tree or baking soda. Insect infestations can be treated by organic pesticides, such as neem oil. Poor soil issues require amending soil with compost or applying fertilizer.

Prevention

• Preventing petunia diseases means ensuring growing conditions that are unfriendly to pests. Avoiding overcrowding prevents both mold diseases and insect infestations. To prevent diseases related to poor soils, amend before planting with compost, and top-dress in the summer to ensure adequate nutrients are available.