Frizzle Top in Cycas revoluta
| Welcome to the PACSOA Palms and Cycads wiki !
If you have any information about this topic, please help by updating this article. Once you are registered you can contribute, change, or correct the text, and even add photos on this page. Click on the edit tab above and play around. Any mistake can be easily corrected, so don't be afraid.
"Frizzletop" is a dieback disease that affects the pinnae on Cycas revoluta plants.
"Frizzletop" occurs in C. revoluta plants primarily because of the absence of (or an insufficient amount of) manganese in the soil.
"Frizzletop" is caused by an excess of lime, resulting in alkaline soil surrounding the affected plant; as a consequence of which manganese is not available to the plant. (Note: Manganese is important to healthy plant growth as it is needed to provide proteins).
"Frizzletop" often occurs in advanced C. revolutas planted in new housing estates, where concrete usage is common; and building rubble is used for fill " thus resulting in an excess of lime in the soil in garden beds.
To restore the plant to normal, it is necessary to increase the acidity of the soil by making manganese available to the affected plant, through the application of Manganese Sulphate.
The application of Manganese Sulphate has a twofold effect:
- by supplying manganese for the plant, and
- by providing sulphur to make the soil more acidic.
Application, by watering-can, of Manganese Sulphate, combined with an accompanying application of a liquid fertiliser (e.g. Nitrosol). Liquid fertiliser is used as a means of assisting the plant to absorb the Manganese Sulphate.
The Manganese Sulphate/liquid fertiliser solution should be watered on to the fronds, the trunk (if applicable) and, also, on the soil immediately adjacent to the plant.
The application of Manganese Sulphate generally should not exceed the manufacturer"s recommendations. One manufacturer"s suggested treatment is to dissolve 10 grams of Manganese Sulphate in 10 litres of water; however, in serious cases of "frizzletop" with mature/trunked plants, it may be advisable to apply up to 20-30 litres of the manufacturer"s suggested mixture, plus a proportionate amount of liquid fertiliser.
Treatment is recommended as soon as the problem of "frizzletop" is noticed. The treatment should be carried out on a seasonal basis after the onset of "frizzletop" is identified, but not during winter. Treatment is suggested in early autumn, early spring and early summer - and such treatment, over a 12 month period, should correct the manganese deficiency.
Once a healthy set of fronds is produced, the cure should be permanent - but to ensure its continued health, the plant should be fertilised periodically with a slow release fertilizer, so as to ensure that a sufficient level of available manganese is maintained.
It is extremely important that the unsightly fronds are left on the plant during treatment, so that they assist in the absorption of the applied solution of Manganese Sulphate/liquid fertiliser by the affected plant.
Craig Thompson and Paul Kennedy (Figure 1 by Craig Thompson)