From our perspective, root rot is one of the most critical threats we face. It occurs when our soil environment remains saturated for prolonged periods, suffocating our roots and creating an anaerobic condition where opportunistic oomycete and fungal pathogens thrive. You will notice our distress through yellowing leaves that rapidly progress to wilting and dropping, despite the soil being wet. Our stems may become soft and mushy at the base. The primary treatment involves a drastic but necessary intervention: we must be removed from the pot. All soft, brown, and smelly roots must be pruned away with sterilized tools. After this, we require repotting into a fresh, well-draining potting mix and a pot with excellent drainage. Adjusting your watering habits to allow the top few inches of our soil to dry out is the best long-term prevention.
This fungal disease manifests as a white, powdery or talcum-like coating on our upper leaf surfaces. It is unsightly and inhibits our ability to photosynthesize effectively, weakening us over time. Unlike many fungi, powdery mildew thrives in humid conditions but does not require free water on the leaf surface, often appearing when days are warm and nights are cool. To treat this, first isolate the affected plant to prevent spore spread. Then, carefully wipe our leaves with a damp cloth to remove as much of the fungus as possible. For more severe cases, apply a fungicide specifically labeled for powdery mildew on ornamental plants, such as one containing potassium bicarbonate or neem oil. Improving air circulation around us by spacing plants apart is also highly beneficial.
We display leaf spot diseases through circular or irregularly shaped lesions on our foliage. These spots can be brown, black, or yellow and are often surrounded by a yellow halo. Bacterial leaf spots often look water-soaked initially, while fungal spots may show concentric rings or a bullseye pattern. These pathogens are typically spread through water splash, so overhead watering exacerbates the problem. Treatment involves promptly removing and destroying the most severely affected leaves. Avoid wetting our foliage during watering. Applying a copper-based bactericide/fungicide can help manage the spread of the disease, but it is most effective when combined with cultural controls like avoiding overcrowding and ensuring we have enough light.
While not diseases themselves, infestations of pests like spider mites and scale insects can cause disease-like symptoms and leave us vulnerable to secondary infections. Spider mites are tiny arachnids that suck chlorophyll from our leaves, causing a characteristic stippling or speckled yellow appearance, often with fine webbing. Scale insects appear as immobile, waxy bumps on our stems and leaf veins, sucking our sap and excreting sticky honeydew that can lead to sooty mold. To treat spider mites, increase humidity around us and rinse our leaves with a strong stream of water or apply insecticidal soap or miticides. For scale, physically remove them with a cotton swab dipped in rubbing alcohol and follow up with horticultural oil applications to smother any crawlers.
