From my perspective as a water lily, the appearance of brown spots and holes is often a direct symptom of an energy crisis. My leaves, or pads, are my solar panels, essential for converting sunlight into the chemical energy (through photosynthesis) that fuels my growth and flower production. When something obstructs this process, the leaf tissue begins to die, manifesting as brown, necrotic spots. If the issue is severe or persistent, the dead tissue can disintegrate, leaving behind holes. A common cause is shading from other plants or structures, or my own older, overlapping leaves. If I am not receiving a minimum of 5-6 hours of direct sunlight daily, my leaves cannot function properly and will begin to deteriorate.
My entire existence is supported by the water in which I live, so its chemical composition is critical. Brown spots can be a distress signal related to nutrient imbalance. A deficiency in key nutrients like potassium (K) or magnesium (Mg) directly inhibits chlorophyll production and enzyme functions, leading to chlorosis (yellowing) and subsequent necrosis (browning) in patches across the leaf surface. Conversely, an excess of certain minerals or a buildup of toxins in the water can "burn" my leaf tissues, also causing brown spots. Furthermore, water that is too acidic or too alkaline can lock up nutrients, making them unavailable for me to absorb through my roots and stems, even if they are present in the pond.
While the previous issues cause spots that may lead to holes, some agents create holes directly. The most common are physical and biological. Fish, particularly koi and certain goldfish breeds, are known to nibble on tender aquatic plants. Their foraging can create irregular holes and tattered edges on my new leaves. Additionally, certain aquatic pests, like the China Mark Moth larva, are specialized feeders on water lilies. These larvae literally cut out oval-shaped pieces from my leaves to construct protective cases. This activity results in very distinct, clean-cut holes rather than the ragged holes left by fish. This type of damage starts as physical removal, not spotting.
When environmental conditions are poor—such as when my leaves are consistently crowded, water circulation is stagnant, or temperatures are high—I become susceptible to pathogenic attacks. Fungal infections, often from genera like *Pythium* or *Rhizoctonia*, can cause brown, rotting spots that rapidly expand. Bacterial infections, sometimes manifesting as black, mushy spots, are equally destructive. These pathogens break down the cell walls in my leaves, causing the tissue to soften, die, and eventually slough away, creating holes. This damage often starts as small, wet-looking spots that quickly turn brown or black and spread.
