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Lily beetle control
The lily beetle (Lilioceris lilii) is the number one pest of lilies. It can reduce a lily plant to nothing in just a few days. They are easy to control.
Both the adult lily beetles (or red or scarlet lily beetle to give it its full name) and the horrible grubs devour lilies - leaves, flowers and flower buds.
The adult beetle is about 5-8mm (about 1/4in) long, bright red with a black head and legs. Eggs are laid on the underside of leaves in groups of up to 12-15; they vary in colour from bright orange to nearly red. The grubs have dirty orangey bodies and cover themselves with their own excreta; this gives them some protection and they can be mistaken for birds' droppings. They then fall onto the ground and pupate.
Adult beetles emerge from the soil from late March to May, laying eggs from April until September. They overwinter in sheltered places, often in the soil but not always near lilies.
It's not only lilies that they have an appetite for - they also go for fritillaries (Fritillaria species) and Cardiocrinum - the tree lily.
One of the best ways to control lily beetle is to inspect plants regularly, and pick off and kill any adults, eggs or grubs as soon as they're seen. I do it early in the morning (before 7.30am) when the adults are sluggish and easy to catch. If disturbed they will drop to the ground on their backs where they can be difficult to spot, so sneak up on them quietly.
Adult beetles and grubs can be controlled, and plants protected, by spraying with Bayer Garden Provado Ultimate Bug Killer* or Scotts BugClear Ultra; the larvae are more susceptible than the adults.
Currently there are no biological controls available for lily beetle.
Use plant protection products safely. Always read the label and product information before use.
* In 2016, Bayer Garden changed the active ingredient in Provado Ultimate Bug Killer to one that doesn't have a systemic action.
The lily beetle is not native to the UK, but it has now become widespread in England and Wales and was first found in Scotland in 2002 and in the Republic of Ireland in 2010.
The RHS is conducting a survey on the distribution of lily beetle; take part in the survey
Buy a range of pest control products from my affiliate companies, Harrod Horticultural and Greenfingers.com
- Bayer Garden, 230 Cambridge Science Park, Milton Road, Cambridge CB4 0WB; firstname.lastname@example.org (Provado)
- The Scotts Miracle-Gro Company, Salisbury House, Weyside Park, Catteshall Lane, Godalming, Surrey GU7 1XE; email@example.com (BugClear Ultra)
If you want to know more, or if you've got a gardening problem you need help with, then send an e-mail to: firstname.lastname@example.org