Orchid Tree Leaves Spots

Orchid leaf spots indicate various problems that may occur among orchid trees.

Orchid trees are native to tropical and subtropical regions in India, China, Africa and Malaysia. The flowers grow in shades of white, pink, purple and red. When orchid trees suffer from problems, evidence of pests, viruses and diseases are often found in the leaves. Spots on the leaves serve as clues, helping gardeners identify and isolate the problem to keep orchid trees healthy.

Growing Orchids

Proper planting of orchid trees reduces the risk of damage caused by various diseases and pests, which commonly strike already-weakened trees. Plant orchid trees in full sunlight and well-drained soil for optimal growing conditions. The tree grows 25 to 30 feet high with a spread just as wide. When perfectly healthy, the leaves will grow in an irregular crown in a deep-green shade, with no fall color change. The trees are cold-hardy to U.S. Department of Agriculture hardiness zone 8.

Disease and Sunburn

Dark spots that appear on leaves with a lighter-brown ring at the edges are indicative of fungal infection. Fungus grows on foliage when orchid tree soil is too moist. Other spots that appear on foliage, either dark brown or whitish in color, may resemble fungus spots but in actuality are the result of sunburn. When sunlight is very strong and bright in spring and summer, orchid tree leaves may be burnt by the excess light.

Pests

Lace bugs feed on orchid tree leaves, which turn yellow after the pests pull chlorophyll from the leaves. Lace bugs leave a black goo behind them as they move from leaf to leaf. The residue resembles small tar spots. Weevils eat holes into the leaves, destroying the foliage. Mealybugs, which look like small pieces of cotton, also feed on orchid tree leaves. Greenflies, blackflies, spider mites, slugs, snails and thrips are all attracted to the leaves, eating small holes along the margins and throughout the leaf. Carefully wipe down infected leaves with pesticides to kill pests and prevent further damage if you notice that leaves are being attacked.

Viruses

Many types of viruses may strike orchid tree leaves when the plant is not receiving enough air flow. Keep trees pruned to avoid these problems. Cymbidium mosaic (CymMV) virus and odontoglossum ringspot (ORSV) virus are the most common viral infections that strike orchid tree leaves. CymMV appears as a pattern of light and dark spots on leaves, though sometimes spots appear black or brown instead. ORSV causes streaky spots to appear on leaves.

References

• University of Florida Cooperative Extension Service; Orchid Trees - Our Beautiful Bauhinias; Gene McAvoy
• University of Florida IFAS Extension; Lace Bug; Doug Caldwell
• University of Florida IFAS Extension; Orchid-Tree; Edward F. Gilman and Dennis G. Watson
• The North of England Orchid Society Website: All About Orchids

Resources

• City of Plantation: Hong Kong Orchid Tree
• University of California Extension: Orchid Tree, Brazilian Butterfly Tree
• Floridata: Bauhinia Variegata