What controls lily beetles?

Plant exclusion, sanitation control, and treatment schedules are ways to get rid of lily beetles. The insects in question (Lilioceris lilii) feed exclusively in larval and mature forms upon the foliage of fritillaries (Fritillaria) and lilies (Lilium) between March and October and overwinter in leaf litter. Their presence therefore may be avoided by not planting fritillaries or lilies, decreased by removing shelters in soil and yard debris and -- when populations are low -- specimens, and eliminated by applying horticultural oil to eggs and home-made insecticidal soap or store-bought insecticidal sprays to larval and mature stages.