Late summer homes

Galls on plants are caused by a variety of insects such as aphids, midges, wasps, or mites. In addition, sometimes galls are formed by infections by bacteria, fungi, or nematodes and are difficult to tell apart from insect-caused galls. Most of the insect galls do little to no harm to a healthy tree.

And some are quite beautiful! Furthermore, all the critters that make these galls are very host specific. In fact, each has a specific type of architecture for their gall homes. So here are a few I found today.

First gall on a Cottonwood! This yellow green gall belongs in the Woolly Aphids and Gall-making Aphids (Eriosomatinae) family. It is probably Pemphigus populicaulis.

Looking on the back of a Hackberry leaf, the Hackberry Star Gall Psyllid (Pachypsylla celtidisasterisca)! The gall formed resembles a flower-like shape! What a wonderful shape!

Same gall as above, but the upper side of the leaf.

Another Hackberry gall, Hackberry Petiole Gall Psyllid (Pachypsylla venusta).

It forms on the leaf petiole and seems to persist on the tree for a long time. It is an easy one to spot in the winter. Winter sounds good today, eh LOL.

Here is the same type gall from above, but maybe last year’s.

The Hackberry Rosette Gall Midge (Celticecis capsularis) finds it special home between the veins! Hackberry seem to host a great number of critters. I love the Hackberry trees.

Many galls will overwinter still attached to the leaves.

The Gall Wasp’s (Amphibolips) home is one of the larger galls I find! It always makes me think of ornaments hanging on the Red Oak.

If you cut one open, you find these radiating “strings” that hold the larva in a very hard center shell.

And just how they get their hosts to build these incredible homes is still a mystery. I just love mysteries. Pretty amazing, eh!

Keep looking!

The more you know, the more you see and the more you see, the more you know.


  1. Those hackberry petiole galls are so diagnostic! I frequently use them to ID the species for my winter deciduous woody plant ID classes.

  2. Also,
    Kimberlie Sasan anticipates many more species of gall wasps await official recognition by science. Sasan is one of the founders of a website devoted to the identification of insects that form galls, called, and she is aware of dozens, if not hundreds, of the insects that remain unidentified.

    1. Alan, Thanks for bringing this up again. The article you mentioned, I posted on the Buzzing Aug 9th. And the link was inside that article. Gallformer. org site has a lot of good photos to help with identifying some galls. Great site. Thanks again!

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