Are the leaves covered with white powder?
Did the margins of the leaf turned brown then over time the browning moved inward?
Are the leaves spotted or blotched?
Are the spots or blotches irregularly shaped, brown, and covering a large portion of the leaf?
Are the leaves skeletonized?
White, powdery patches on the leaves are caused by a fungal disease Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining them and any surrounding plants. Water plants from below to keep foliage dry. Any affected leaves should be cut off and removed. The appropriate fungicidal spray will protect your plant from further infections.
Dry, papery leaves are caused by leaf scorch. If the crispy, dry appearance shows up on leaf margins first, then progresses to the entire leaf, they are suffering from leaf scorch. This often happens during hot, dry weather when moisture evaporates before the plant can absorb it. Without moisture, the leaves are unable to cool and easily become scorched. A good soaking may restore a leaf-scorched plant if the damage isn’t too severe.
Irregular brown spots on leaves are caused by a fungal disease - Leaf blotch. Leaf blotch may spread over leaves on the whole tree and even lead to defoliation. To protect your tree clean up and destroy fallen leaves to remove overwintering spores, cut all affected leaves, and destroy them.
Leaf spots are caused by several different species of fungi. Fungi love wet weather, so prevent leaf spots by ensuring good air circulation around your plants. Infected plant parts should be removed and destroyed.
Skeletonized leaves are caused by Japanese beetles, pests that can seriously damage foliage. Handpick adult beetles into a can of soapy water but make sure to wear gloves as Japanese beetles are blister beetles. Apply parasitic nematodes to the soil to limit beetle grub populations. Use pyrethrin powder or neem oil as a last resort.
If much foliage has been eaten starting from the top of the tree down the culprits are caterpillars of the White-Marked Tussock moth. Control their numbers by scraping off and destroying patches of their eggs when you see them. With serious infestations, you'll have to use insecticides.
https://www.doityourself.com/stry/buckeye-tree-diseases-and-pests
Ellis, B. W., Bradley, F. M., & Atthowe, H. (1996). The Organic gardener's handbook of natural insect and disease control: a complete problem-solving guide to keeping your garden & yard healthy without chemicals. Emmaus, Pa.: Rodale Press.
Sreten null
Hi! I’m Sreten Filipović. I graduated from the Faculty of Agriculture at the University of Belgrade, with a master's degree in Environmental Protection in Agricultural Systems. I’ve worked as a researcher at Finland's Natural Resources Institute (LUKE) on a project aimed at adapting south-western Finland to drought episodes. I founded a consulting agency in the field of environment and agriculture to help farmers who want to implement the principles of sustainability on their farms. I’m also a founding member of the nonprofit organization Ecogenesis from Belgrade whose main goal is non-formal education on the environment and ecology. In my spare time, I like to write blog posts about sustainability, the environment, animal farming, horticulture, and plant protection. I’ve also published several science-fiction short stories.
You can find me on LinkedIn at https://www.linkedin.com/in/sreten-filipovi%C4%87-515aa5158/
