Troubleshooting
Comb Cycad problems — and how to fix them
Comb Cycad (Cycas pectinata) is generally low-drama, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Cycad scale (Aulacaspis yasumatsui)
This armoured scale is a serious threat to cycads worldwide; colonies encrust leaflets and petioles with white waxy scales, causing yellowing and eventual frond death. Treat with repeated applications of horticultural oil or systemic imidacloprid soil drench; quarantine new plants before adding to a collection.
Manganese deficiency
In alkaline or waterlogged soils, manganese becomes unavailable; new fronds emerge pale yellow-green (interveinal chlorosis). Apply manganese sulphate as a foliar spray or soil drench and correct soil pH if above 7.5.
Prevent comb cycad problems before they start
Most comb cycad issues are care-mismatch, not bad luck. Dial in the basics:
Comb Cycad problems — FAQ
Why is my comb cycad cycad scale (aulacaspis yasumatsui)?
This armoured scale is a serious threat to cycads worldwide; colonies encrust leaflets and petioles with white waxy scales, causing yellowing and eventual frond death. Treat with repeated applications of horticultural oil or systemic imidacloprid soil drench; quarantine new plants before adding to a collection.
Why is my comb cycad manganese deficiency?
In alkaline or waterlogged soils, manganese becomes unavailable; new fronds emerge pale yellow-green (interveinal chlorosis). Apply manganese sulphate as a foliar spray or soil drench and correct soil pH if above 7.5.