How do I identify and control Lily Beetle?

Q: How do I identify and control Lily Beetle? 

What they look like:

Lily beetles are charming, fascinating and an entomologist's dream. It’s a pity they are also so devastating. Protected by a scarlet-red, shell suit of armour to deter even the most persistent of predator, they are around 8mm long.

What they damage:

With the help of their grubs, will strip bare your lilies and fritillaries. And because this damage happens in summer, next year's bulbs are severely reduced in size resulting in poor flower production. After a few years, you can forget about any lily blooms. If you spot an adult you will have grubs. Both, however, are ready for you.

Why they are clever:

Adults, due to their garish appearance, have a couple of tricks up their sleeves to avoid capture. They will sense you approaching and will fall from the plants, onto their backs on the soil surface. And that makes them difficult to spot as their undersides are black. The second defence mechanism is that if caught they do two things. Firstly they squeak - only faintly but enough to put off some potential threats but more importantly to alert fellow lily beetles to do that falling off the plant trick. Secondly they - how to put this delicately? - release gas when being hassled. This whiff alerts other lily beetles in the vicinity to jump off the leaves onto the soil. Once on the soil they wait a bit and crawl back up.

The grubs have a disgusting defence strategy of smearing themselves in their own faeces. And it works (no surprise there) - birds don’t fancy that type of snack and move elsewhere, leaving the voracious grubs to get on with stuffing their greedy mouths with your lily leaves.

How to sort:

You’ve got to sort this lot out before they destroy your lilies. Check every day for signs of damage. Do it carefully and and gently - sneak up on them, catch them and….what you do next is up to you. Sorry, but you have to do the same with the grubs. Gloves might be a good idea. You can spray them (check out our pesticides ) - this is more effective on the softer grubs than the hard shelled adults. Some say that a garlic spray  (take 4-5 garlic cloves, crush and add to litre of water, leave to infuse for a couple of hours, add strained liquid to a plastic spray bottle and spray on plants) works well. It might mask the smell of the blooms though. Whatever action you take, do check the undersides of the leaves as that is where the beetles like to mooch about.


Good luck - it’s a battle but one worth fighting. 

Garden Pests