Plant Doctor Archive

Citrus verrucossis

MY question is about a well-established lemon tree. The fruits, even when they are green, get a whitish mark all over them. The tree produces tonnes of fruit but it is useless for making lemon curd. What can I do to fix this? It has happened for about four years. Is there a safe spray to use on fruit?

YOUR tree is suffering from citrus verrucossis. It is a common problem when the weather is cool and wet. This fungal disease infects the fruit when it is young. It is safe to spray with a copper-based fungicide as the fruit begins to develop in the late summer and autumn.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.