Lily beetles (Lilioceris lilii) are small red beetles that feed on the leaves, stems, flowers and flower buds of lilies, fritillaries and other members of the lily family (Liliaceae).
Besides being small and fast-flying, lily beetles have a special defense mechanism that makes them difficult to catch; when they feel threatened, they drop to the ground and curl up with their black abdomen outwards, making them difficult to spot. They can also start screaming when they feel very threatened!
That's why it's a good idea to keep your hand under them when trying to catch them. Alternatively, you can put some blank paper under the lilies so they can't hide. NOTE: Captured beetles must be destroyed immediately.
The best products against lily beetles
For lily beetle control, we recommend the product Pireco®, which is available in both capsule and liquid form. Pireco® is a biostimulant that strengthens plants, making them more resistant to lily beetles and other pests. Pireco® is based on herbs and is completely insecticide-free. You can buy Pireco® below:
3 methods to control lily beetles
Below you can read about the different methods to control lily beetles. Please note that the methods are sorted in order of priority and that you should therefore start with method number 1, then 2 etc.
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- Trapping: Unlike many other insects, in many cases you can eradicate the local lily beetle population by “manually” trapping and killing them. As described above, just make sure to keep your hand (or a piece of white paper) under them when capturing them, otherwise they can easily camouflage themselves in the ground. Make sure to capture ALL beetles and destroy them immediately. You should inspect all plants in your garden once a day and exposed plants twice. Remember to also check for larvae and eggs; they are usually under the leaves (remove and destroy them). Also check the soil under the plant for beetles, larvae and eggs.
- Garlic: Stick 2 – 3 cloves of garlic cloves (no more) into the soil around each plant stalk. This has a deterrent effect on beetles and works for most garden owners. We recommend trying this method before trying the spray described below, as garlic is a cheap, easy and 100% organic solution. However, be aware that garlic in excessive amounts – which includes garlic extracts – can inhibit plant growth.
- Insecticides: In well-stocked garden centers and some webshops you can buy various insecticides that can be used to control lily beetles. In Denmark, however, it is difficult to find products specifically designed to control lily beetles, but you can try other insecticide sprays. The product Pireco almost always gives good results. However, please note that some products can be harmful to the environment and endanger animals and plants and that the Environmental Protection Agency does not recommend the use of toxic products.
How do you find lily beetles?
If small red or orange beetles are crawling around on your lilies, they are probably lily beetles. They can also be found in other places such as between tiles, under tools, boxes, jars, etc.
A black, sticky, brown (or red/orange) lump on a lily leaf is a common sign of lily beetle presence; the lump contains the lily beetle's small larva. If you discover such a lump, destroy it immediately and check the other lily leaves and plants carefully.
If you have the time, check your lilies daily for lily beetles and their eggs.
Characteristics of the lily beetle
- Adult lily beetles are 6-9 mm long
- They primarily lay their eggs on lilies and fritillaria
- Lily beetles fly fast and are good at hiding
- Larvae are very small and gray-green
- The upper side (the beetle's wings) is red, while the underside (the beetle's legs, eyes, antennae and head) is jet black
Lily beetles and cardinal beetles
Lily beetles can easily be confused with cardinal beetles (Pyrochroa), although there are several differences:
- Lily beetles are herbivores, whereas cardinal beetles are carnivores that primarily feed on insects. Therefore, lily beetles are mostly found on the flowers they feed on (e.g. lilies), whereas cardinal beetles feed on all kinds of flowers, shrubs and trees
- Physically, lily beetles are also more round and compact than the elongated cardinal beetles. Lily beetle wings are also shinier than those of cardinal beetles
Lily beetles can also be confused with ladybirds without black dots – ladybirds are more round in shape than lily beetles.
Life cycle
Lily beetles overwinter in the soil or under the plant remains of the lilies they feed on during the summer months (but not necessarily in the soil around the lilies). They emerge in the spring when they start eating the fresh, newly emerged lily leaves and also mate.
Females can lay up to 450 eggs each season and typically lay around 12 eggs in irregular lines along the midrib of the lily's leaves. The eggs hatch after 6-10 days.
The larvae then begin to feed on the outer part of the leaf and work their way up towards the rest of the plant. In total, they eat for up to 24 days.
They then bury themselves in the soil where they form a pupa from saliva and soil particles. After 20 days, they emerge as adult lily beetles and continue to feed on the lilies until winter. In some cases, they can go through this cycle more than once a year.