I live in Tucson and have had a terrible time with white grubs in my vegetable garden. So far I have tried diatomaceous earth, dug into the garden Spring and Fall, and Grub Beater From ARBICO ORGANICS. Grub Beater was my last trial. I followed the directions but, when I started digging for my Autumn / Winter garden, there were literally dozens of still-living grubs. I dug everything out, sifted through a hardware screen, and pulled and stomped all the grubs I found. I then planted some tomatoes and peppers. I guess I didn't get all the grubs, because most of those plants are now dead. Just wilted away and no roots left. My garden is a variation of the square foot concept, utilizing six 4' x 4' squares. The ground around it is undisturbed desert hard-packed dirt.
I would appreciate and advice anyone can give me.