Greetings. I am an Impatiens plant, a being of vibrant blooms and lush foliage that brings joy to many gardens. Yet, my existence is not without its vulnerabilities. I am susceptible to several common diseases that can diminish my beauty and vitality. From my perspective, here is a detailed account of these ailments and the conditions that lead to them.
This is, by far, the most frequent affliction I endure. It begins subtly, as a few white, powdery spots on my upper leaves. To you, it may look like dust, but to me, it is a parasitic fungus (often Podosphaera xanthii) siphoning my nutrients. It spreads rapidly, coating my stems and flower buds in a suffocating film. This blanket blocks sunlight, crippling my ability to photosynthesize and produce food. My leaves become stressed, turning yellow, curling, and often dropping prematurely. My growth becomes stunted, and my blooming ceases. This fungus thrives in the very conditions I dislike: warm days, cool nights, high humidity, and poor air circulation around my leaves. It is a constant battle for light and air.
While powdery mildew attacks from above, a more sinister threat often lurks below in my soil. Caused by fungi like Pythium, Rhizoctonia, or Fusarium, these rots are a consequence of drowning. When my roots are forced to sit in waterlogged, poorly drained soil, they cannot breathe. They soften, turn dark brown or black, and begin to decay. This severs my critical connection to water and nutrients in the soil. The rot then travels upward into my stem, often appearing as a soft, mushy, darkened area at my base. From your view, I will wilt dramatically, despite the wet soil, and my entire structure may collapse. Overwatering is not an act of kindness; it is a sentence to a suffocating death for my root system.
Another group of fungal foes manifests as unsightly blemishes on my foliage. Fungi from the Alternaria and Cercospora genera land on my leaves, especially when water sits on them for extended periods. They create small, circular spots that may be brown, black, or tan, sometimes with concentric rings or a yellow halo. These spots are necrotic tissue—parts of my leaf that have been killed by the fungal invasion. As the spots enlarge and multiply, they cause extensive damage to my photosynthetic surface. Severely infected leaves yellow and drop, weakening me significantly and leaving me exposed to further stress.
This is a particularly devastating disease, as it is a viral infection with no cure. I contract it primarily from the feeding of western flower thrips. These tiny insects pierce my cells and inject the virus directly into my system. The symptoms are varied and destructive: black spots and rings on my leaves, stunted growth, malformed leaves, and sunken, discolored lesions on my stems. The virus disrupts my fundamental cellular processes, leading to a general decline. Unfortunately, once infected, I remain a permanent host and a source of the virus for other plants, often necessitating my removal to protect the rest of the garden.
