Currently viewing the category: "Galls"

Galls on Ocotillo?
Location: Organ Pipe Cactus National Monument, AZ
February 28, 2011 9:39 pm
My field crew and I came across this ocotillo that has what appear to be galls on it. Are these deformities produced by an insect, and if so, which one? Thanks!
Signature: Ed Kuklinski

Galls on Ocotillo?

Dear Ed,
According to the Morton Arboretum website:  “Galls are abnormal growths that occur on leaves, twigs, roots, or flowers of many plants. Most galls are caused by irritation and/or stimulation of plant cells due to feeding or egg-laying by insects such as aphids, midges, wasps, or mites. Some galls are the result of infections by bacteria, fungi, or nematodes and are difficult to tell apart from insect-caused galls. Seeing the insect or its eggs may help you tell an insect gall from a gall caused by other organisms.
”  What you have photographed does fall into the “abnormal growth” category, but we cannot say for certain that they were caused by insects.  The desert is a harsh climate, and there might be many things other than insects that might have caused this unusual phenomenon.  Perhaps one of our readers will provide some insight.

Galls on Ocotillo?

White Oak gall
Location: Great Smoky Mountains National Park, TN
December 16, 2010 10:57 am
I’ve been seeing this gal on white oaks the past couple years in and around Great Smoky Mountains National Park TN. I looked at the picture on your site and didn’t see any that seemed to match. Wold love to have an idea of what kind this is and assume it is a wasp gall?
Signature: Ken Voorhis

Galls on White Oak

Hi Ken,
Thanks for sending your photos.  Galls are growths that can be attributed to many different kinds of insects including wasps and flies as well as to certain mites and other causes that are not related to arthropods.  In the case of Gall Wasps in the family Cynipidae, the Gall is a growth on the plant, often the leaf, that provides food for the larval wasp and does not harm the tree.  Oak trees are probably the most common host to Galls.  There is much diversity in Gall Wasps and we do not have the necessary expertise to classify your particular galls, but you can view some of the genera posted to BugGuide.  There is also a section of unidentified Galls available on BugGuide.  Alfred Kinsey, who gained notoriety in the 1950s with his studies on human sexuality, was an entomologist who specialized in Gall Wasps prior to turning his attention to the private lives of humans.

Galls on White Oak

Thanks Daniel, If I find anything more I’ll forward it to you.
Ken
Ken Voorhis            Executive Director
GREAT SMOKY MOUNTAINS INSTITUTE AT TREMONT
Great Smoky Mountains National Park

White Oak Gall (you don’t have a picture of.)
Location: Murrysville, East of Pittsburgh, PA
October 28, 2010 4:18 pm
Hello Bugman,
I took pictures of some galls on my white oak tree today (10-27-10) I couldn’t find any pictures of these either on BugGuide or on this site. They are ONLY on my white oak tree – not on any other oak tree in my yard. (Pin oaks, shingle oaks) And there are hundreds of these galls. I find it interesting that they have turned pink as the leaves have turned red, since they are made of leaf tissue. They flick off the leaf easily and are wet when squished. This tree is about 15 years old and I do not recall ever seeing these galls on it, although I have seen other types. Thought you might like these pictures for your files.
Signature: MPK

Galls on White Oak

Dear MPK,
There does seem to be an infinite variety of Galls that can be found on oak trees, and we wish Alfred Kinsey were still alive and working to classify the Gall Wasps that produce these harmless growths.

Galls on White Oak

Bug eggs on Oak leaves
Location:  Southeastern Iowa
August 16, 2010 2:35 pm
The attached photos show a multitude of bug eggs on the leaves of the oak tree in my backyard.
I cannot identify what bug these eggs are associated with. I would like to know if there is any danger to the tree’s health or to my home from these bugs.
Jay D

Oak Gall

Hi Jay D,
This is not an egg.  It is a Gall.  A Gall is a growth on a plant caused by an wasp, midge, mite, or occasionally another type of insect.  According to BugGuide: “There are more than 2,000 gall-producing insects in the United States; 1,500 are either gall gnats or gall wasps.
”  The insect produces an enzyme that causes the plant tissue to grow in a deformed manner, and this growth serves as food for the developing gall larvae.  It is generally believed that the Gall does not harm the plant.  We believe your Gall is a Gall Wasp in the family Cynipidae, but we could not find a conclusive match on BugGuide.  There is one image of an unidentified Gall Wasp Gall on BugGuide that looks similar to your Gall.   BugGuide gives this advice for Gall identification:  “Gall insects (and mites) are usually highly specific about what kind of plants they use, and even what part of the plant. To maximize your chances of getting a gall identified, record the plant species (include photos of the leaves, flowers, fruits, etc. if you’re not sure), and if it’s a leaf gall, note the position on the leaf (if it’s not obvious from the photo): upper side or underside; midrib, side vein, or somewhere else. Also note whether or not the gall is detachable, the size of the gall, and anything else distinctive about it that may not be clear in the photo. With oaks in particular, which are hosts for hundreds of kinds of galls, every little detail can help to narrow down the options.”  An interesting side note is that Alfred Kinsey who shot to notoriety in the mid twentieth century with his ground breaking studies on human sexuality began his professional career as an entomologist who specialized in the study of Gall Wasps.  He approached his studies on human sexuality with the same rigor that he used in collection over 1 million specimens of Gall Wasps.

Oak Galls

bug larvae on Spanish Stopper
Location:  Florida Keys
August 11, 2010 11:30 pm
Hi!
I’m just curious as to what these things are on the underside of Eugenia foetida.
Susan

Unknown Galls

Hi Susan,
These appear to be Galls.  Galls are growths that appear on plants and they are often caused by insects, but not always.  We have not had any success determining what has caused these Galls.  When they are caused by insects, they are usually very plant specific.  Perhaps one of our readers will be able to assist with the proper identification of your galls.

Thanks Daniel!
Everyone from the park (volunteer for Dagny Johnson Bot. SP) tells me they are galls but that seems to be enough of an answer. I would like to know more. I would guess that they are caused by insects as they are on so many Spanish Stopper especially this year.
Susan

What is This?
July 8, 2010
Dear Bugman,
Recently, I went hiking to an old monastery in Turin, Italy. The trail was punctuated by large cement crosses that had something to do with the myth of the Stations of the Cross. Worried about having a Jesus overdose, we sought an alternate route. Along the way, we came across this deformed tree. Thinking it was perhaps the work of Satan, we went back to the JC trail.
I am not convinced that these odd thorny growths are from the devil’s hand. Seems he could do a lot better than this. I suspect it’s a bug!
Any ideas?
Regards,
Godless Hiker
Turin Italy

Grape Tube Gallmakers

Dear Godless Hiker,
These odd thorny growths appear have been produced by the Grape Tube Gallmaker,
Cecidomyia viticola, a species of Midge.  The plant appears to be a wild grape which would support our identification.  We ran a similar photo from Alabama in 2008.  Galls are generally considered to be growths on plants that may be caused by insects including wasps and flies, or by mites or other arthropods.  BugGuide indicates: “Gall insects (and mites) are usually highly specific about what kind of plants they use, and even what part of the plant. To maximize your chances of getting a gall identified, record the plant species (include photos of the leaves, flowers, fruits, etc. if you’re not sure), and if it’s a leaf gall, note the position on the leaf (if it’s not obvious from the photo): upper side or underside; midrib, side vein, or somewhere else. Also note whether or not the gall is detachable, the size of the gall, and anything else distinctive about it that may not be clear in the photo. With oaks in particular, which are hosts for hundreds of kinds of galls, every little detail can help to narrow down the options.”

Grape Tube Gallmakers