As a cultivated geranium, my life is one of vibrant beauty but also constant vulnerability. From my perspective, my greatest threats come from tiny invaders and silent sicknesses that can compromise my health from root to petal. Here is a detailed account of the adversaries I face in gardens and homes across the United States.
Several small pests see my succulent stems and tender new growth as an endless buffet. The most common is the aphid. These tiny, soft-bodied insects cluster on my undersides of leaves and stems, piercing my tissues to suck out the nutrient-rich sap. This feeding weakens me, causing my leaves to curl, yellow, and distort. Even worse, their sticky excrement, called honeydew, attracts sooty mold and can spread viral diseases between me and my plant neighbors.
Another significant threat is the spider mite, especially in hot, dry conditions that I dislike. These minuscule arachnids are nearly invisible until their damage is done. They feed on individual plant cells, creating a stippled, yellowed pattern on my leaves. A telltale sign of their presence is the fine, silken webbing they spin on my foliage before my leaves turn brown and desiccate. Whiteflies are also a nuisance; when I am disturbed, these tiny, moth-like insects flutter up from my leaves, having been feeding on my sap and weakening my overall vigor.
While sucking insects are a persistent annoyance, the caterpillars of the geranium budworm (also known as the tobacco budworm) are a direct and voracious assault. This pest is particularly devastating to my prized blooms. The small caterpillars bore into my unopened flower buds, feeding from the inside and causing the buds to blacken and drop without ever opening. If they move on to my leaves, they chew irregular holes, severely compromising my ability to photosynthesize and robbing me of my ornamental beauty.
Perhaps the most insidious threats are the diseases that attack me from the soil up. The most notorious is Botrytis blight, or gray mold. This fungus thrives in cool, damp, humid conditions. It appears as a gray, fuzzy mold on my dying flowers, leaves, and stems. It quickly spreads to healthy tissue, causing large, soft, brown patches of rot that can consume entire sections of me if left unchecked.
Even more fatal are the various root and stem rots caused by water molds like Pythium and fungi like Rhizoctonia. These pathogens lie in wait in waterlogged, poorly draining soil. They attack my root system, causing it to turn black, mushy, and ineffective. Above the soil, my stems wilt and darken at the base, leading to a rapid and irreversible collapse. Overwatering is the primary cause of this, creating the perfect environment for these destructive organisms.
A specific and highly contagious bacterial disease, Xanthomonas hortorum pv. pelargonii, or bacterial leaf spot and blight, is a grave concern. It begins as small, water-soaked spots on the undersides of my leaves that gradually develop into brown, sunken lesions. The bacteria then spread through my vascular system, blocking the flow of water and nutrients. This causes a progressive wilting, where my leaves yellow and wither between the veins, eventually leading to a systemic collapse and death. This disease can spread quickly through splashing water and contaminated tools.
