I haven't logged into this thread in such a long time, and just happened to see this thread revived when looking for info for a friend in Irvine and thought we should respond.
In a nutshell, we followed up with the city of Irvine, and they do in fact spray Roundup in the Avocado Orchards. They gave us a long list of chemicals, but that was the one listed at the very top.
What was alarming to us was the timing - we had just moved in not even a few weeks after they had sprayed, and that is when we started to notice the symptoms. I had horrible rhinitis, so did our kid, and other people that came to the house also noticed symptoms. We traveled to the East coast for a few weeks and our symptoms also vanished completely.
I'm not saying it was the chemicals, because it literally could have been the off-gasing from the new paint and appliances, or it could also have been the construction dust as well. But the thing is, we have lived in new contsruction homes before and NEVER had this problem. This was the first time I ever had horrible rhinits symptoms ever in my life, and I am not prone to getting allergies.
The real alarming thing was that we heard a neighbor of ours had kids who had even worse symptoms. One had facial tics, and the other one had a rash after swimming in the pool right across from the Orchards, around the same time they sprayed in that area.
Needless to say, we were not going to put our family at risk, so we moved out of the area. We felt fortunate enough that we could make that decision for the best interest of our kid, given the circumstances of just having moved in. We ended up doing an out of State move anyway to save money financially, so the timing of it ended up working out in our favor.
I personally, no matter how small the risk, would never live near any Orchards where they are spraying roundup when having kids of any age in the home.
I felt like, given the information in hand, that we had enough to make a sound decision. I wish everyone luck in theirs, and I'm sure we are in the minority in terms of moving out, but I was not about to risk our child's health at all. It's not worth it to us.
Also, I am not an anti-vaxxer or a crunchy as they call it

I was in the medical field for over 10 years. I consider myself to be of sound mind when it comes to making medical decisions like this, and for our health, and especially our child's health, the risk was not worth staying.
Hope this info is helpful, and feel free to DM us if you have any additional questions.