Greetings, caretakers. We, the Peace Lilies (Spathiphyllum spp.), are generally resilient houseplants, but we can fall victim to several ailments that compromise our vibrant green leaves and graceful white blooms. Understanding these issues from our perspective is key to restoring and maintaining our health.
Our most common and serious affliction is root rot, primarily caused by the water mold pathogens *Pythium* and *Phytophthora*. This is almost always a result of what you call "overwatering." Our roots need both water and air. When constantly submerged in heavy, soggy soil, they suffocate and begin to decay. These weakened roots are then invaded by pathogens that rapidly spread, turning them mushy and brown. From our viewpoint, this feels like a slow suffocation, cutting off our ability to absorb water and nutrients, which causes our leaves to wilt, yellow, and collapse despite the wet soil.
Our broad leaves are also susceptible to surface-level invasions. Two common issues are:
Cylindrocladium Root Rot: Ironically named, this fungus often first appears as leaf spots. You will see dark brown, blackish spots often with yellow halos on our lower leaves. In advanced stages, it attacks the roots and crown, causing wilting and collapse.
Bacterial Leaf Spot: Caused by pathogens like *Acidovorax avenae*, this manifests as small, wet, soggy-looking spots on our foliage. These spots can quickly enlarge, become angular as they are constrained by the leaf veins, and give our leaves a tattered, unhealthy appearance. High humidity and water splashing on our leaves facilitate the spread of this bacteria.
We are often plagued by tiny insects that pierce our leaves and stems to feed on our sap. This drains our vitality and can introduce toxins or viruses.
Mealybugs: These pests appear as small, white, cottony masses in our leaf axils and on the undersides of leaves. Their feeding causes yellowing, stunting, and a general loss of vigor.
Spider Mites: Nearly invisible to your eye, they create fine, delicate webbing on our foliage. Their piercing mouthparts cause stippling—tiny yellow dots—which can merge into large, bronzed areas. We find them particularly troublesome in hot, dry indoor conditions.
Aphids and Scale: These also feed on our sap, often excreting a sticky residue called honeydew, which can attract ants and lead to the growth of sooty mold, further blocking our sunlight absorption.
It is crucial to understand that many of our disease problems begin with environmental stress. Incorrect light (too much direct sun scalds our leaves, too little weakens us), improper watering, low humidity, and extreme temperatures weaken our natural defenses. A stressed Peace Lily is much more susceptible to pathogen attack and pest colonization. What you may diagnose as a disease is often a secondary infection that took hold after our growing conditions became less than ideal.
