Hi Vacationed to Mi. from Az.
When we returned back to Az's heat 110 degrees one of my mesquite trees was brown. 3 years ago planted now it's about 12 to 15 feet high with a spread of about 12 feet. trunk is about 4" diameter. lots of honey sap
Water type drip system with 3,1 gal emitters on a daily 7am for 16 min. I have 3 more trees that look great.same size and watering systems.
Also last year when I came back from Mi. all 4 of my trees were blown almost over by the high winds of the monsoons, I lost many good size branches, the landscaper planted all the trees on a 2 foot high by 10 ft long mound maybe 5 ft wide. he came back and re staked
all the trees they grew like teenagers wild and sprouting everywhere.
This year I decided the monsoons would twist the outer limbs and rip the main branches off and split the weak joints. But I think I waited to late in the season June 25th. So I decided to trim the tree. Any branch growing down cut. any branches rubbing another came off. Now I had to trim the wild growth extending in a way that it would start twisting like Chubby Checker.
then thinning the center so the wind would pass through the center. I did not touch the canopy.
I did this to all four of my trees.
But this year are area never got a bad monsoon storm.just heat as usual.
everything was fine when I returned except one dead mesquite in full hot sun all day. perhaps a fungus I see at least 6 trees in my neighborhood dead also?
is there a insect or grub responsible ? how do I check this out ?
I'm hoping the tree may come back with TLC
all opinions welcome

Did you check all your drip emitters? They can clog, and critters can chew through the lines for water.

I don't think you an kill a Mesquite. Do a scratch test (if you can get close enough ). Scratch the bark with something sharp. If the layer under the bark is green, the tree is fine. If its brown ot hard, the branch is dead.

I have mesquites that are never watered and they do fine in Phoenix heat. I agree, it would be almost impossible to kill one.

Hello My fellow Gardeners
To Caro, Daisyl and Plantmanager. Yes I did check the emitters first thing. The ground around the root system is still soft enough but yet firm and able to take water to the roots. When I returned there was only one of three branches coming off the main upper trunk that was still green but this only lasted a week,. then it to went brown. On one of my long morning walks i saw another dead tree in another neighbors yard. so I began to notice all within the three block are more dead trees, perhaps 6 or 7. I tried contacting Az agricultural dept. about a fungus or a bug infestation that may be arriving in our area, I never got an answer.
I have to suspect really that my careless pruning at the wrong time did excessive damage to the tree. But I see the landscapers doing it next door.
I'm going to do as Daisy said, cut into the bark to see if there is a chance that the tree will come back.
I would like to thank all of you for a quick response
Robert1938

Some herbicides can cause what you're describing. Any chance all the trees in the neighborhood were accessible to vandalism? Ugly thought, I know. Were all the dying trees mesquites?

Hello Needrain, Thanks
I have processed this thought and know I had not used any weed sprays in a while, My property is completely surrounded by a 8 ft wall ( Az. fences ) as for the other trees some are in an open area maintained by the local landscaping co. the neighbors tree about the same age and size as mine is also enclosed in a walled area. I do plan on talking the this person soon.
All the homes in our area are only 3 years old as are all our landscaping.

Robert1938

There is more than one kind of mesquite. The impossible to eradicate variety that grows widely in Texas is the Honey Mesquite. Truthfully I've never known anyone to deliberately transplant one, though I've met a very few people who profess to like them . I think in your area that may not be the variety that landscapers use. I found this link:
https://www.desertharvesters.o...
which may be of interest to you. It concerns the two varieties that are presumably the ones commonly used by landscapers in the Sonoran Desert. It may or may not be helpful, but it might be a starting place to investigate what may be happening with yours. Other than here, of course, which tends to be a really good source for information.

needrain said:The impossible to eradicate variety that grows widely in Texas is the Honey Mesquite. Truthfully I've never known anyone to deliberately transplant one, though I've met a very few people who profess to like them

You know one person who deliberately planted a Honey Mesquite...

Thanks to all who have offered their input.
This is what has transpired this morning. I grabbed my tools and dug around the trunks root system and came across a few grubs 4 at the most. i believe normal in moist ground.
Next I went about 36" above the base and started lifting the dead bark aha!
I found only one but I identified it on the tree borers site. What I found was a
Flathead borer 3/4' long skinny with a round head like a white tadpole
it had runs all under the bark with plenty of saw dust these insects/ worms
will cause the water deficiency to kill a tree. but my question, why? so fast ? it was healthy looking in June ? So perhaps i'm not the bad guy here after all?.
My next plan is to call a licensed Arborist. to help save the other 3 trees.
I Will keep you informed.
Robert1938

Flat Headed Borers! There's not much you can do except pull the affected tree before they spread. Burn the wood - you don't want them hanging around your property.

OK folks here is where i'm at, My tree is dead. it must have been dying prior to the insect infestation, they attack dead trees or sick trees. and finish the job.
I have ordered from Amazon an insecticide for around the roots to feed into the tree by way of watering It's called Monterey Once A Year insect Control. Use once a year. I have 3 mores trees to protect and I will replace this tree with a new Mesquite but with the knowledge I have learned I hope to prevent this from happening again. Being from Michigan and 81 yrs old, one would think I know enough how to care for trees I grew up around every kind plus fruit's
But this desert heat is very new to me as well as trimming prior to monsoon season.
Thanks again for all the care and thoughts you have shared with me on this journey
robert1938

DaisyI said:

You know one person who deliberately planted a Honey Mesquite...

Uh oh! Well, it may look like crap with dead and breaking limbs, but at least it won't die. Hopefully it won't try to take over the whole world in your area .

robert1938 said:OK folks here is where i'm at, My tree is dead. it must have been dying prior to the insect infestation, they attack dead trees or sick trees. and finish the job.
robert1938

Yes, that's how it works. I don't think they bother a healthy tree. When I've deliberately worked at killing the mesquites here, they can die overnight or with a slow, slow decline. But those borers recognize and attack the dying and sick trees. Sometimes the effect is very sudden, but the tree was already very sick. Most often, they get on a recently dead tree and immediately consume what they want, leaving lots of piles of sawdust at the base. If a tree dies in the winter, those trees usually aren't eaten. Those that get sick or die in the warm months get attacked quickly. It's one way I know I've successfully eliminated the tree. I think they don't consume really dry, dead wood - only the wood that is newly dead or nearly so. Based on my observations, FWIW. I was going to next ask you if you had seen any sign of borers. For you, I think that still leaves the question as to why it died in the first place. Potent herbicides are not a preventative to an infestation of the borers. They don't care why a tree is dead or dying, but they probably didn't cause its demise.

Thanks Needrain
I'm going to water the other trees just in case
with Monterey once a year insect control Wish my luck
Neighbor

Robert1938

One thing that speeds the borer work is summer pruning. I know you are trying to save the tree by pruning, but you are also inviting insect infestations.

thanks Daisyl

Robert you are the first person I've ever heard of. that planted and watered a mesquite tree. Mesquite grow here in the millions and you can't kill them. Farmer's spend a ton on labor to get rid of them and keep them out of the pastures, and in a few years their back.

Watering a Mesquite tree at the wrong time of the year can cause problems. If your practices fall out of the guidelines of a normal growing season, the tree will respond with disease and will develop weakness's. I recommend not using emitters on mesquite because of your recent casualty.

Second tree dies.
Interesting August 2020 Just returned from Mi. after a two week Vacation.
My Mesquite tree in my front yard area Is 85% dead all brown ?
One main branch still living. The tree is on a drip system once a day 1/2 gal. the temp. before I left and after 110 degrees . no rain hot winds.still 110 degrees.
I'm sure no one is vandalizing my trees. I hired a recommended Tree company to pruned my trees in June. Three other trees are fine just like last year ?
I've never read about a tree turning brown in the summer and coming back.
when it cools down I'll do some bark removal and dig for a cause.

I think it's time to quite the Mesquite trees.