Treating Nipple Gall on Alstonia Scholaris (Saptaparni) Trees

Your Alstonia scholaris trees have blister-like galls on leaves—even on young foliage. Cutting one open revealed black material inside. This is nipple gall, caused by tiny insects (related to cicadas and leafhoppers) that lay eggs on leaf undersides. The hatched larvae trigger abnormal leaf growth, forming protective galls.

Primary Control: Remove Affected Leaves

This is the single most effective step. Pull off and destroy every galled leaf—do not compost or mulch them. Each gall can harbor hundreds of insects. Since not all leaves are affected, this is manageable. The tree will replace lost foliage on its own.

Secondary Treatment: Neem Spray

After leaf removal, spray the trees weekly with neem for a month, then monthly. Neem disrupts insect feeding and reproduction. If new galls appear, remove those leaves too. Neem is available as liquid, powder, or cake—mix with water and apply as a fine mist using a pump sprayer or even a spray bottle. The key is thorough coverage, especially on leaf undersides.

Why This Works

Insects inside galls are protected from sprays. Removing galls eliminates the current generation. Neem deters new egg-laying. Consistency is crucial—repeat weekly at first, then monthly through the growing season.

By next year, with diligent leaf removal and neem applications, the infestation should be gone.