Can I spray nematodes recently purchased from my local nursery onto my soil here in Phoenix, Arizona (Maricopa County) zone 9 in the current month of April 2024 while our temperatures are already around 90 degrees during the day? Night time is down in the low 60's. I read that late evening or early morning is ideal depending on the outdoor temperatures. Also, should I water my fruit tree wells and above-ground garden beds before spraying onto the soil the nematodes? I recently applied
Grub Free Zone III just last week. Not sure if that product contains the chemical you mentioned. But I will investigate that in more detail.

Thank you so much

The "Grub Free Zone 3" contains some sort of long acting imidacloprid.
It is not recommended for fruit trees. It is a long acting systemic insecticide that will kill pollinators that visit the flowers, then end up in the fruit. (If you get any fruit after you've killed off the pollinators.)
I don't know if the nematodes are killed by imidacloprid, but if you have already killed the grubs, there will be nothing for the nematodes to eat, and they will die.
The live nematodes can only be stored for two weeks, in the refrigerator. If you did not store them this way, they're probably already dead.
Live nematodes can be applied in SOIL temperatures up to 95 F.
Anyhow, I do welcome you to the forum. I think everyone here will suggest that you please carefully read and follow the instructions on product labels. It's always best to follow the manufacturer's instructions, not random advice from online chats. (Myself included there.) Or garden center employees.
If you can't find those instructions, they are readily available online.
https://www.arbico-organics.co...
https://www.fertilome.com/Prod...