Disease in my linden tree

(Question)

Hello Master Gardener,
I live in Toronto. Purchased/ planted a linden tree last summer. A month after I planted it, I saw the leaves being unhealthy. This spring the tree is fully infenstated again with the same disase. The tree has grown actually, which tells me the roots are doing fine. But the leaves look terrible. Can I treat it? How? Would the issue disappear.
The tree is still under warranty. Should I return it?
Thanks so much,
Irena

(Answer)

Your photograph appears to show spindle galls, which are caused by tiny Eriophyid mites, an insect. Although they are unsightly, these rarely threaten the life or health of any affected tree, and there is no treatment recommended.  Here is a description from another Toronto Master Gardener post:

“The Eriophyid mites are blown by the wind or carried to your tree by birds and insects. The adult females overwinter in cracks in twigs and lay their eggs in the spring. Each can lay up to 80 eggs in a month and each egg will develop into an adult in one to two weeks. The adults feed by sucking up the contents of plant cells. To protect itself, the linden forms a barrier of plant tissue that is the gall.  Spindle galls are formed on leaves and resemble the spindle of a spinning wheel – shorter at the ends than in the middle, hence the name. You may find that the number of galls varies considerably from year to year. The damage caused by the galls is cosmetic so control is not recommended.”

To read more about Eriophyid mites and spindle galls, click on the link below to access a good article on the gardenguides.com website:  Linden Eriophyid Gall Mite Control