Hackberry Psyllid - Pachypsylla celtidisasterisca

Moved

… Charley Eiseman, 12 February, 2015 - 6:24am

Moved

Moved from Unidentified Galls. Frassed a bunch

… John R. Maxwell, 2 August, 2010 - 5:17pm

Hackberry

You've already figured out that the tree is Hackberry (Celtis occidentalis); your photos show good indicators of that species: asymmetrical leaf bases, hairy veins on underside of leaf, and zigzagging twigs.

… John Pearson, 28 July, 2010 - 9:08pm

Hackberry galls

I think you've got two different things here. I think the disk-shaped ones are Celticecis midge galls, but apparently it's not certain what exact species produces them. There are many different kinds of fancy-shaped midge galls on hackberry, and only some have been described (same deal with hickory). The more bloated ones, which I presume are the ones that are bowl-shaped on the upper surface of the leaf, I think are Pachypsylla but not positive. Felt doesn't illustrate many of the psyllid galls on hackberry for some reason. Sometime (maybe this winter) I'll try and track down the original descriptions of these--hopefully they are illustrated--and see if I can make sense of them.

Can you double check and see whether the disk-shaped ones are fully detachable (only on one surface of the leaf) or have the beginnings of a bowl-shaped depression on the other side? If the latter, maybe I'm wrong about them being midge galls, and maybe you're right that they're all the same.

… Charley Eiseman, 28 July, 2010 - 5:44am

Image

Seems to match this one. Galls on bottom and both types (balls and disks)

… John R. Maxwell, 28 July, 2010 - 10:30am

Okay

There are photos of similar galls (discs) in this book (1) -- that must be what I was looking at before. They are identified only as "hackberry button galls," the products of psyllids. Based on other sources (e.g. Felt) it seems that all psyllids that make galls on hackberry belong to Pachpsylla. I'm still hopeful that I can figure out the species if I go to the primary literature. I'm still inclined to think you have two different kinds, both made by psyllids, and I don't think the ones with bowl-shaped depressions would be considered button galls... but maybe I'm wrong, and somehow the disks distort into balls/bowls when they open to let the adults out.

… Charley Eiseman, 28 July, 2010 - 10:47am

Nothing conclusive

other than "Yes Pachypsylla". The disks contained smaller nymphs so they may be younger, but that still doesn't rule out another species in the same genus. The structure is also similar and I can imagine a growth from a disk to a sphere that could occur, but that doesn't mean that it does occur.

… John R. Maxwell, 2 August, 2010 - 12:44am

Info

After checking it seems:
All of the galls (off-white disks and "little green apples") are on the bottom of the leaf.
All of the "little green apples" galls have the gaping hole on the upper surface of the leaf.
All of the off-white disks with red markings have the image just added on the upper surface of the leaf.

Without following one gall through its life I can't be sure if the depression deepens and becomes a hole or if they are 2 different galls.

… John R. Maxwell, 28 July, 2010 - 10:20am

Midge galls

Based on that, I feel pretty good about calling the disks midge galls... although, if you still have them, you can settle it for sure by breaking them open (both kinds) and seeing what's inside.

… Charley Eiseman, 28 July, 2010 - 10:31am