Live oak bud gall

Texas live oak (Quercus fusiformis) and Southern Live Oak (Quercus virginiana) in Austin and Houston have a small, persistent bud gall that was, to my knowledge, never reported before I observed it in 2022. You can see the observations here; so far @jeffdc, @currenfrasch, and I are the only ones who have reported it on iNat.

I was quite confused about the phenology of the gall last year. However, I've been tracking them as they developed across the last year in relatively large numbers, and it makes a bit more sense now. They start developing on buds at the tip of new growth in July and grow slowly. Their phenology closely matches agamic generations of galls like Disholcaspis cinerosa and Druon quercuslanigerum. By October the larva is visible but only occupies the tip of the gall; by December, the larva has eaten the gall tissue. The specimens I collected in Austin were still larval on January 1 but had pupated by February 4. I'm not sure exactly when they'll start to emerge but I think it's likely to happen over the next two months.

I'd love to have people look for this gall over the next few months to 1) assess the limits of its range and 2) collect more galls to guarantee we can rear adults and create a more diverse specimen set for the description. I would be surprised if it isn't found in DFW and throughout Texas, possibly into Oklahoma. I'd also expect it to be present on live oaks as far east as Florida but I'm less confident of that. It would be very interesting to know if it's found on Quercus geminata.

To look for it, scan large numbers of branch tips looking at the end of last year's growth, (ie, not the new spring growth if you're looking after budbreak). They're hard to distinguish from normal buds at first so you may be fooled but they are more conical, larger, and grey rather than brown. It helps to have something to magnify the branch tips at least a bit. In Austin, I've found them in 3 places but they are far more abundant on a couple trees than the others. It may take some looking to find a good site for them.

Posted on Φεβρουάριος 09, 2024 0249 ΠΜ by megachile megachile


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Φεβρουάριος 4, 2024 10:39 ΠΜ CST


I certainly will! What is the best storage container to keep developing pupa in?

Ps. I only know of this gall because of you!

Αναρτήθηκε από currenfrasch 4 μήνες πριν

I suspect these dry out quickly so I might try keeping them in a water-tight container like a ziploc bag. But at this point it's hard to be sure so worth experimenting.

Αναρτήθηκε από megachile 4 μήνες πριν

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