Lily Beetles or Scarlet beetles are 6mm – 8mm long with black heads and love eating the leaves, flowers and seedpods of lilies and other members of the lily family. Don’t mistake them for ladybirds!
Between April and September the beetles lay eggs on the undersides of leaves. After a week they hatch into reddish-brown maggot-like grubs, and feed on the same parts of the plant as the parents. Possibly to deter predators or disguise themselves, the larvae cover themselves in their own wet, black excrement.
Lily beetles are beautiful insects, but they’re capable of stripping lilies, fritillaries and giant lilies (Cardiocrinum) back to a few meagre stems.
Are your Lily leaves shredded and covered in brown-black droppings?
Pick off the grubs and adults as soon as you see them. The adults will drop to the ground at the slightest touch, so spread newspaper under the plants to catch them. Be quick and crush them under foot or they’ll fly off.
Seen the lily beetle? The RHS would like to know.
As part of research, The RHS would like to know where the lily beetle has been seen.
Please submit your records via their lily beetle survey (expected time to complete survey = two minutes).