My calamondin has a clear sticky residue on some of the leaves.
Just started. What is it? How do I treat this?
Thank you for contacting Toronto Master Gardeners. We do receive a number of questions about growing citrus trees and the attached links offer insight on the subject. Here are some answers to your question:
The Calamondin (Citrofortunella microcarpa) is a strong plant which prefers to be outdoors in it’s native range and makes a good houseplant in our climate, benefitting from some time outdoors in good weather. The Calamondin (Citrofortunella microcarpa) is susceptible to only a few pests. One is scale, the other is mites. I’ve included a site with images and ideas on how to get rid of scale. Scale insects pierce the leaf to suck the sap which then drips onto other leaves, this causes stickiness.
With mites you would see yellowing leaves and sometimes small webs and the plant would look sickly. To be absolutely sure you can put a white paper underneath and shake the branch. If there are mites they will fall on the paper.
The following link provides some general information about growing citrus trees indoors.