I am in California zone 8a and no, we did not physically identify the insect. We were told the damage looks like thrips, and also we had had damage on trees that were also associated with thrips by people with more experience than I have (on pears).
Also, I was told that sometimes you don’t notice the thrips or damage until they’re already gone.
Does this problem look like something else to you?
The reason I asked is because I had symptoms on my own nectarines that looked like thrips but couldn’t find any of the pests. If I’d known you lived in CA I wouldn’t have asked as I’m in NY and for the first time I saw the same symptoms in many of the orchards I manage. No one has identified the presence of thrips yet.
It turns out that you can get similar symptoms from ovule injury during spring freeze events, and we had such an event and a lot of symptoms in stone fruit that isn’t part of the usual thrip damage.
I already know that trip damage is very common on the west coast, but much less common here.
We actually had snow during the bloom period. So you just might be right about that.
The symptoms of stone fruit freeze ovule damage runs from !: Getting no fruit set on trees that bloomed beautifully- male flowers being somewhat tougher than the “eggs”. 2: Having peaches and nects that form and grow until they reach about golf ball size, stop there, and eventually rot, often when other fruit on the tree is just starting to ripen. 3: Brown rot problems that start on the interior of even perfect looking fruit fruit and cannot be reached with fungicide. 4: Pitch pockets in plums and other seed issues in all stone fruit. Pitch pockets are hard spots near the pit but not pieces of fractured pits. 5: fractured and cracked pits. 6. deformed fruit that resembles thrip damage. 7: Most of the fruit setting towards the interior of the tree under the shelter of the branches reducing brix.
In my orchard I had at least one of those symptoms on all my peaches, nects and plums. The trees with only one symptom were those that bloomed and were highly tended by pollinators but set no fruit at all or just a very light crop.
The surprising thin is that only J. plums were showing green when temps dropped to 19 degrees in early spring and many of the J. plums set very well.
Zephyr, white nectarine, picked today. It is a large piece of fruit. All between 8.5-10.5 oz.
Freckle Face, yellow nectarine, on average is about 7 oz.
My trees had symptoms 2,3, 5,6 & 7.
@Ahmad
My late nectarine, September Free.
I think the “free” refers to free stone. The last ones were picked yesterday. It is mildly sweet. Without summer heat, there is little sugar. It would be a good variety for much warmer zone, I think.
We added sugar 
. For nectarine crisp.
