Insecticide is the worst thing you can use on your lawn (after fungicide), because it kills out an entire class of beneficial microbe in the soil - the microarthropods. Yes, avoid the use of insecticides as much as you can. Grub infestations are usually predictable. If you have a swarm of beetles around your porch light in May or June, then you have a better chance than most of getting a grub problem. Those beetles lay eggs in the soil which hatch and eventually become the grubs. Your lawn should be able to tolerate up to a dozen grubs per square feet. If you would like to do that research right now, you can. If you have a lot more than a dozen per square foot, then you can apply a grub killing product. Otherwise, join the majority of us who rarely-to-never use insecticide.

These grubs in San Diego or other parts of S. California are almost always Green Fig beetle larva (Cotinis mutabilis) not june beetle larva (but they are related). The larva love to eat compost, the bugs are huge and eat decaying fruit but I haven't seen them cause damage to fruit or plants. However, we are having a problem in that we mulched and composted over our front lawn to convert to vegetable garden & orchard, and included some uncomposted coffee grounds and tea from cafes. Now we have grubs and then we have raccoons coming at night to dig up the grubs, and they frequently dig out plant starts and tear up newly seeded beds. Ugh.

Around here they eat grass roots, tomato roots, and everything else under the soil. I put Bayer killer stuff in my pots so my hostas are safe from them as well as the weevil larva. Get rid of them!!! -Babka

More than likely the eggs that produced the grubs you saw were in the potting mix. Grubs do migrate through the soil some and if that pot was sitting on soil infested with grubs they might have maybe migrated up into the pot, but the reality of that happening is fairly low.