Katsura tree: Aromatic Plant

Leaf tip necrosis, also known as tip burn, is a non-infectious environmental condition where the tips and edges of leaves turn brown, dry, and crispy. This occurs due to various stress factors affecting the plant's ability to maintain healthy tissue at the leaf extremities.

Sunscald is physical damage that occurs when intense sunlight and heat strike plant tissues that are not acclimated to such exposure. It typically follows heatwaves, heavy pruning, transplanting, the removal of shade, or intense winter sun followed by freezing nights. On fruits such as tomatoes, peppers, cucumbers, apples, and pumpkins, it manifests as pale, bleached, or whitish patches that later become tan or brown, sunken, and occasionally leathery or blistered. Leaves may appear scorched at the margins, but the primary diagnostic sign is light-bleached, papery, or corky areas on the side facing the sun. On young trees (such as maple, birch, and various fruit trees), the bark on the south or southwest side may darken, crack, or scale following sunny winter days and cold nights.

Water deficiency occurs when a plant cannot absorb enough moisture to meet its transpiration and metabolic demands. Also known as drought stress or underwatering, this condition deprives cells of turgor pressure, leading to wilting, leaf scorch, and — if prolonged — permanent root and tissue damage. It is one of the most common causes of houseplant decline and is fully reversible when caught early.

Powdery mildew is a common fungal disease caused by various fungi species including Erysiphe, Podosphaera, Oïdium, and Leveillula. It affects over 10,000 plant species worldwide. The disease thrives in warm, dry climates with high humidity and appears as a distinctive white powdery coating on plant surfaces.