Lily Leaf Beetle
Lilioceris lilii
A bright scarlet beetle whose adults and larvae feed only on true lilies and fritillaries and can defoliate a plant completely. The slug-like larvae carry a shield of their own excrement on their backs.
🔎 How to spot it
Adults are about a quarter inch long and bright scarlet red with a black head, legs, and underside, and they squeak when handled. The larvae are plump and orange to brown but hide under a wet, black fecal shield. Eggs are orange and laid in irregular lines on the undersides of leaves.
🥀 Damage it causes
Both adults and larvae chew the leaves, buds, and flowers, and the larvae do the most damage, able to strip a plant bare. Defoliation saps plant vigor and ruins bloom. True lilies in the genus Lilium and fritillaries are the only plants on which it breeds; daylilies are not hosts.
🛡️ Prevent it
Scout plants beginning in early spring and handpick adults, eggs, and larvae, which is very effective on a few plants. Check the undersides of leaves for the orange egg rows. Some lilies, such as certain Lilium henryi, Lilium speciosum, and Black Beauty types, show more resistance.
🧯 If it is already here
Neem products work best on very young larvae, while spinosad controls larvae and pyrethroid insecticides such as permethrin kill adults. Repeat handpicking through the season for small plantings. Introduced parasitic wasps provide biological control in parts of the Northeast.
💡 Good to know
There is one generation a year, and adults overwinter in soil and debris, often away from the host plants. The fecal shield on the larvae is a defense that makes them unappealing to predators. Daylilies, despite the name, are never attacked.
🌱 Plants it attacks
3 plants in the library can be attacked by this pest
For educational and informational purposes only. Pest control advice is general guidance drawn from university cooperative extension sources; always identify a pest positively and read and follow the label on any product before use, especially around food crops, children, and pets.