Diseases like downy mildew, powdery mildew, root rot and pests like aphids and spider mites can affect impatiens flower. Disease risks are minimized by good air circulation, spacing and watering at the bottom of the plant. Do not overcrowd and promptly remove infected leaves to prevent spread of problems. By routinely checking plants for insects and applying insecticidal soap or neem oil as soon as a pest problem is detected, impatiens will remain healthy and vigorous, and continue to produce beautiful flowers.