Spray your lilies as soon as you see the very first beetle show up since it will put out a scent that will lure lots more to the area. Spray with Bonide Bon-Neem 2. It is a combination of two organic insecticides. The pyrethrin in it will kill the adult beetle on contact and the neem oil in it will disrupt the feeding of the larvae so they never reach maturity. Always read and follow the directions on the label. To avoid harming bee with the pyrethrin, spray early in the morning before the bees become active. Once the spray dries, it won’t harm the bees.