I lost 3 of 4 beautiful pepper plants in August. They just wilted, fruit and all. When I pulled them up their roots were brown. I recently read an article in my Garden Club newsletter to be on the lookout for a root weevil (diaprepes abbreviatus) that is apparently doing damage to crops in California. When they posted a black and white pic, I knew I had recently seen a crowd of them on my garden fence. They were there over the course of a week and I finally just pulled up the milk weed which seemed to be where they were gathering. My question to Southern California gardeners is do you have them and have you had damage similar to mine? They are know to be damaging over 270 plants including citrus, hibiscus, avocado, loquat and oak.
Here is a link that might be useful: Root weevil