Scarlet lily beetle
The scarlet lily beetle (Lilioceras lilii) may look attractive, but this red lily beetle is the scourge of lily growers. The lily beetle can do a huge amount of damage to lilies and other members of the lily family and needs to be controlled whenever it is seen.
How to identify scarlet lily beetles
The adult lily bug is 6-8mm long with a black head and legs and bright red wings. From early spring until autumn, it is easy to spot these relatively slow-moving red bugs on lilies, but this lily pest has a cunning defense mechanism that makes physical capture difficult. When disturbed, it drops to ground level and turns upside down, where its black underside is difficult to locate.
Lily beetle eggs are orange/red and laid in clusters on the undersides of lily leaves.
Scarlet lily beetle larvae are active from mid-summer and are even more sly than the adult beetle. The 6-8mm long, round-bodied grubs cover themselves with their wet, black excrement (called ‘frass’). This protects them from predator attacks.
Scarlet lily beetles symptoms and damage
Adult scarlet lily beetles eat holes in the leaves of lily plants, often causing leaf drop which weakens the plant. Lily beetle larvae scrape away the underside of the leaves, leaving white or brown patches. Lily beetles will also eat flower buds, lily flowers and seed pods. Over time, the lily bulbs become smaller and in subsequent years the flowers become fewer or might fail completely.
As well as attacking true lilies (Lilium species), they will also attack other members of the lily family such as snakeshead fritillaries (Fritillaria meleagris), crown imperial (Fritillaria imperialis) and giant Himalayan lilies (Cardiocrinum giganteum).
Scarlet lily beetles control and treatment
How to get rid of red lily beetles?
There are just a few methods of lily beetle control. Here we’ve listed a couple of ways to stop the lily beetle, both cultural and chemical.
- Remove any adult scarlet lily beetles by hand and dispose of them. They are quite dozy early in the morning, so this is the best time to catch them. Using a tissue or piece of kitchen towel, wipe off the larvae rather than picking them off, or remove a whole leaf where they are feeding and dispose of it.
- Where this isn't feasible or practical, you can control them by spraying a lily beetle insecticide onto affected plants. The best ones to use are systemic insecticides. Lily beetle spray tends to be more effective against the grubs than the adults, which can fly in from neighbouring gardens. Apply a further treatment three weeks later to help control any grubs that may have hatched from eggs laid before the first spraying.
To protect bees and pollinating insects do not apply to plants when in flower. Do not use where bees are actively foraging. Do not apply when flowering weeds are present.
How to prevent scarlet lily beetles
- Check your plants. From early spring start to check lilies and fritillaries frequently for signs of scarlet lily beetles, so that you can remove them before a damaging population has developed.
- Encourage wildlife in the garden. Birds, frogs, wasps and predatory ground beetles eat lily beetle grubs and sometimes adult beetles and provide a form of red lily beetle organic control.