A beetle which destroys lilies has been reported in parts of Cornwall and north Devon.
The beetle can strip a lily plant in a matter of days
The Royal Horticultural Society (RHS) says the scarlet lily beetle and its larvae can strip plants in days.
The Society describes it as a "red plague".
RHS entomologists have been tracking the beetle since it became established in Surrey in the 1940s.
It remained confined to that area until the mid 1980s.
But in the last 20 years it has spread to many other parts of the country, and has now been spotted in gardens in the South West.
Entomologist Andrew Salisbury said: "This beetle reproduces rapidly and can strip a lily plant in full flower in a matter of days."
The reasons for the beetle's rapid spread are not clear, but the growing popularity of lilies and climate change are among factors being considered.
The larvae have dirty orange-red bodies with black heads and they are rotund with a humped appearance.
The larvae normally cover themselves with their own slimy black excreta and can be mistaken for birds' droppings.
With adequate food, they reach up to 10 millimetres in length, at which stage they pupate.
Gardeners have to rely on chemicals or hand-picking the beetles to control the pest.