Greetings from the garden bed. We, the Delphiniums, stand tall and proud, our vibrant spires reaching for the sun. However, our majestic presence is often challenged by numerous adversaries that threaten our health and beauty. To ensure our prosperity, it is vital to understand these threats from our perspective.
Our tender new growth and the undersides of our leaves are prime targets for colonies of aphids. These tiny pests pierce our tissues to suck out the nutrient-rich sap, which weakens us, causes our leaves to curl and distort, and stunts our growth. Furthermore, they excrete a sticky substance called honeydew, which attracts sooty mold, further inhibiting our photosynthesis. Even more insidious are the cyclamen mites, too small to be easily seen. They infest our flower buds, causing them to blacken and abort before they ever have a chance to open into the magnificent blooms we are known for.
In the cool, damp darkness of night, a more visible threat emerges. Slugs and snails find our young, succulent seedlings and emerging new shoots in spring utterly irresistible. They use their rasping mouthparts to chew large, ragged holes in our foliage, and can completely decimate a young plant overnight, severing stems at the base. Waking up to find our forms ravaged and our leaves skeletonized is a dishearteningly common experience.
Perhaps the most devastating attack comes from within. The larvae of the Delphinium Leaftier moth and other borers literally get under our skin. They tunnel into our stems, hollowing us out from the inside. The initial sign is often a sudden wilting of a healthy-looking stem, even when the soil is moist. Upon investigation, you will find the interior of our stem filled with frass (excrement) and the culprit itself. This internal damage blocks the vascular tissues we use to transport water and nutrients, leading to rapid collapse and death of the affected stem.
Fungal diseases thrive in the conditions we sometimes prefer. Powdery mildew manifests as a white, powdery coating on our upper leaves, especially in times of high humidity with poor air circulation. While it rarely kills us outright, it mars our appearance and weakens us by stressing our photosynthetic capabilities. Far more serious is Crown Rot or Root Rot, caused by various soil-borne fungi like *Sclerotium rolfsii*. This disease attacks our crown and root system, the very heart of our being. It causes a sudden wilting, yellowing, and collapse of the entire plant, often with a white fungal mat visible at the soil line. Once established, it is almost always fatal.
Caused by the bacterium *Pseudomonas syringae pv. delphinii*, this disease is a nightmare. It begins as dark, water-soaked spots on our leaves, which rapidly enlarge and blacken, often causing entire leaves to die. It can also cause black streaks on our stems, leading to their collapse. This bacterium spreads easily through water splash, unclean tools, or even by hand, and it can devastate an entire planting if not checked promptly. It thrives in wet, cool conditions, making spring a particularly vulnerable time for us.
