Rent Shop Volunteer Join

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

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
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

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 Pests Questions

Spots on bark of Mountain Ash from Engadine MI
April 30, 2012 - I have a mountain ash that is about 5 years old & have just noticed white, patchy, scaly looking spots on the bark. Is this something to be concerned about???
view the full question and answer

Spots on non-native naval orange trees from Stockton CA
October 20, 2012 - I have two mature Navel Orange trees. One tree has developed spotty chlorophyl depleted areas that were not on the oranges when they were smaller. In addition, the oranges on both trees are smaller ,...
view the full question and answer

Black walnut herbivory
June 13, 2005 - We moved to Texas just about a year ago and have loved it here. This past January we visited the Wildflower Center and obtained some black walnut seeds. Up until last night the tree was doing well p...
view the full question and answer

Problems with Monterrey Oak in Austin
March 26, 2013 - We had a local tree service plant two Monterrey Oak trees on 4/2/2012. At the time we noticed that woodpeckers had had a field day on the trunk bark of both trees with the most damage being on the lar...
view the full question and answer

Eliminating wood roaches from hardwood mulch from San Antonio TX
February 05, 2013 - How can I eliminate the numerous wood roaches in my hardwood mulch that I get for free from the city of San Antonio?
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.