Chinkapin Oak - Stress?

Question: Hi,
My Chinkapin Oak is seven years old. The leaves are curling and leathery. Is this stress, or something else?
I apply a Bayer or Fertilome systemic insecticide each year because it had some bugs a few years ago. 
Historically it has only received water when the grass is watered (two or three times a week for 40 minutes each time). I've dumped a five gallon bucket of water on it once a week for the last couple of weeks, just in case it isn't getting enough water. 
I don't apply any fertilizer specific for the tree. I've only applied one application of lawn fertilizer this year.

responder: Alison O'Connor, PhD  Replied June 24, 2024, 6:57 PM EDT
response: Hi Mike,  What type of fertilizer did you use this spring? Have you done any weed control on the property, such as in the landscape beds, the lawn, or in the area behind the tree?

responder: The Question Asker Replied June 24, 2024, 7:21 PM EDT
response: Oh my...maybe we did it to ourselves.The fertilizer was a half rate application of a high nitrogen lawn fertlizer, but no weed or bug killers in it. We have been spraying for weeds in our pasture. We had SCORCH applied with a boom sprayer. That was about 50 feet from the tree (and farther out). My wife has been spot spraying 2,4,D and VISTA with a backpack aprayer. She's gotten to within 25 feet or so.  For what it's worth, all of the weed treatments are in the morning when there is minimal or no wind. We've been working with Larimer County Weed District. Last fall, Maxine cautioned us that our weed treatment might have stressed some of my vegetable garden plants. Could we be creating the same problem with the oak?  (In case you are interested, you helped me diagnose some weeds in my lawn a year or two ago. I tried to kill them, aerated, overseeded, etc. At the end of the day, I think it was a draw! I'm lowering my weed standards haha...)   On Mon, Jun 24, 2024 at 4:57 PM Ask Extension <<personal data hidden>> wrote:

responder: Alison O'Connor, PhD  Replied June 24, 2024, 7:39 PM EDT
response: Hi Mike,  Unfortunately, yes, this looks like herbicide damage from 2,4-D. While you followed all the right protocols when spraying, there may have been some volatilization if the temperatures went above 85 degrees the day you sprayed...or even a day or two after. Fortunately, the damage doesn't look too bad and the tree should recover next year.  Wait to spray when we have a string of cooler days - easier said than done :)

responder: The Question Asker Replied June 24, 2024, 9:08 PM EDT
response: That’s really interesting. 2,4-D must be really good at what it’s supposed to do but it sure wreaks havoc with its neighbors. We’ll look for cooler stretches (I don’t think we knew that could help)Mike On Jun 24, 2024, at 5:39 PM, Ask Extension <<personal data hidden>> wrote:   ﻿

responder: Alison O'Connor, PhD  Replied June 24, 2024, 10:47 PM EDT
response: It's ok - it's actually kind of common this year. I think it's because we had such hot weather for so long. We usually have a couple hot June days, but there was a long stretch at the end of May and then in June. Fortunately trees are pretty resilient. And the leaves will still be able to photosynthesize. They might drop a little early, but they shouldn't show any damage next year.