En Español

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

Vines free from cutter ants from Caldwell TX
November 14, 2012 - What are some climbing vines cutter ants won't eat
view the full question and answer

Green cyst-like growths on Texas persimmon leaves
September 20, 2013 - We have a mature Texas persimmon. We just noticed some green cyst-like growths on the tops of some of the leaves. The undersides of those leaves have black spots where the growths are. They looks like...
view the full question and answer

Caterpillars on Milkweed in MA
January 23, 2016 - I have found every year a black/red caterpillars on my milkweed. They eat everything! I have never been able to find out what they are or how to get rid of them.
view the full question and answer

Defenses against imported red leaf beetles on lilies
August 06, 2007 - I've recently discovered small red beetles of some kind on my lilies, which they are happily devouring. I've been picking them off with my fingers and squashing them, but I'd like a better alterna...
view the full question and answer

Control of ball moss in oak trees
March 23, 2007 - I live in San Marcos, Texas and I have a two acre lot with lots of oak trees. Most of these trees have so much ballmoss attached to them that the leaves and branches are not visible anymore. Is ther...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center