A guest post by Anne Stine, one of our Hubbard Fellows.  All photos are by Anne.

A couple of weeks ago (in mid-October) I noticed unusual egg cases about 2-3 inches off the ground on the base of Siberian elm saplings in one of our more tree-infested tracts.  I noticed the casings because I was basal bark treating their hosts. The placement of the cases and the size of the host trees were pretty uniform.  The egg cases themselves look like limpets and are about 1 cm wide by 2 cm long.  I know they’re egg cases and not cocoons because I snapped one open to see what was inside.

Egg case, with PVC kill-stick for scale.

What species are these mystery eggs, and do they parasitize Siberian elms? If anyone has answers to these questions, I’d like to hear them.  It would be great if SOMETHING ate Siberian elms.  Combating invasive/aggressive trees is a major task here on the prairie. Deciduous trees are especially hard to kill.  Their root reserves make them more resistant to fire, and they sucker when girdled.  Because of these limitations, basal bark treatment (kill-sticking) in combination with removal of parent trees is often the most sensible course of action. Kill-sticking is problematic because it is extremely time consuming, and is ineffective on large saplings with thicker bark.  Here’s hoping these little eggs grow up to be hungry adults with a taste for elm!

Open egg case on rubber herbicide glove (for science!). Back-side up.

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Egg case frontal view.

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