Explore Plants

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 

Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.

rate this answer
Not Yet Rated

Thursday - July 14, 2011

From: Deerfield, WI
Region: Midwest
Topic: Pests, Trees
Title: Tree with brown spots on leaves containing caterpillars
Answered by: Nan Hampton, Eric Beckers, and Mike Quinn

QUESTION:

We have a new little tree we planted in our yard and I went over to admire it and on each leaf there is a brown spot in which little worms are living. They are alive and moving around in the pocket the brown on the leaf has made for them. I showed my husband and he immediately cut the tree down and burned it, but I've never seen anything like this before and I'd like to know the name of the tree disease.

ANSWER:

Technically, your tree's problem was an insect infestation, not a disease.  I consulted with a tree expert with the Texas Forest Service and an entomologist and both agree that your tree was infested with insects called leaf miners.  The little worms you saw were the larvae of the adult insect.  The adult female insects stick their ovipositors through the surface of the leaf and lay their eggs there.  The tiny larvae hatches and feeds on the leaf tissue layer between the upper and lower surfaces. The insect might be a moth, a beetle, a fly, a wasp, etc.   If you had told me what kind of tree it was, I might have been able to be more specific as to what kind of insect the culprit was.  Here is information about oak leafminers, the birch leafminer in Wisconsin, and the spotted tentiform leafminer from Wisconsin Master Gardener Program.  Wisconsin also has problems with leafminers in agricultural crops—corn blotch leafminer, vegetables, and alfalfa.  For mature ornamental plants the leafminers' effects are mostly cosmetic and don't usually severely damage them.  They can survive considerable leaf loss, but it may affect their vigor and make them more susceptible to other insects or disease.  Here is an article on controlling leafminers from Planet Natural and one on controlling birch leafminers from the University of Minnesota Extension Service.

By the way, our tree expert said that your cut tree could possibly, given the rainfall you receive, resprout from the roots (if your husband didn't dig them up) and grow up to be perfectly fine.

 

 

 

More Trees Questions

Plant identification of shrub with thorns and purple flowers
July 05, 2011 - I have a small tree or shrub, it has very small or thin thorns on the branches. It blooms in April / May. The flowers are purple. My mother-in-law said that it has been around for over 100 years, b...
view the full question and answer

Growth rate of the American beech tree from West Hartford CT
May 25, 2010 - What is the growth rate of an American beech tree?
view the full question and answer

Why is my Chinkapin oak losing its leaves this spring?
June 02, 2009 - We have a chinkapin oak that was planted about two years ago in our front yard. This year it leafed out nicely but about a month ago the leaves began to roll up, then dry out and fall off. It seems ...
view the full question and answer

Failure to bud out of Shumard oaks in Floresville TX
April 16, 2010 - Question: I have a Shumard red oak (9-10ft tall) that I planted last October as its leaves were turning a brilliant red color. However, it's the only tree that did not bud this spring. I scraped t...
view the full question and answer

Need suggestions for plants for a privacy screen for a pecan orchard in Chappell Hill, TX.
September 21, 2011 - Mr. Smarty Plants, My family has just begun converting our land in Chappell Hill, TX (Washington County) into a pecan orchard. We had to clear a lot of the overgrowth around the edge of the proper...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.