Furry White Things on My Myers Lemon Tree

Q. Last year we bought a Myers lemon and planted it in a large pot. We got more than 30 lemons off this little tree. I noticed a lot of sap near the base of the tree, then a bunch of furry little things on the trunk and some branches. They scrape off easily. I’m guessing they are the cause of the sap.

Cottony cushion scale on lemon

More of the same

A. You are right. This is cottony cushion scale, an insect, on your lemon tree. Those little furry things are homes to the scale insect. They live under those furry things where they are protected from pesticides and predators.

            Once in a while they come out and build a larger, furry home or find a mate. When they do, this is called their “crawler” stage, when they are most vulnerable to pesticides and predators.

            What’s interesting are the ants that you didn’t mention. These small, scale insects feed on the sugary sap inside the tree. While feeding on this sugary sap, a sugary concoction comes out the other end which some ants love.

            These ants move these insects to new growth in the spring where feeding is a lot easier than at the tough, woody base of the tree. In these new locations, ants “herd” them like cattle and protect them from marauders.

            From your picture it doesn’t look like you have very many on this tree yet. Take some alcohol and a cotton swab and dab them off. If there were lots of them you could spray horticultural oil several times during the year, particularly during tree growth periods.

            These oils suffocate the crawlers and keep it from spreading while the older ones eventually die off. Apply these oils three or four times during the year at times when temperatures are cool. By the way, it also helps a lot to control any ants in the area.