The scarlet lily beetle, red lily beetle, or lily leaf beetle (Lilioceris lilii), is a beetle, native to Eurasia, that feeds on the above ground parts of lilium including the leaves, stem, buds, and flowers. Species lilies, Asiatic, Oriental, martagon and other types of lilies are all susceptible. Fritillaria are also at risk from this beetle.
These beetles were first discovered in eastern Canada about 50 years ago, and have gradually gained a foothold in most of New England, New York, Washington, Oregon and central and western Canada.
The adult lily beetle is about ¼–⅜ inch in length, with relatively long legs and antennae. Its forewings are bright scarlet and shiny. Its underside, legs, eyes, antennae and head are all black. It has large eyes, a slim thorax, and a wide abdomen.
The beetle overwinters in the soil and emerges early in spring to feed and mate. The female lays up to 450 eggs each season in groups of approximately 12 on the undersides of the lily leaves. The reddish orange eggs are arranged along the midrib of the leaf and hatch in 2-3 weeks into light brown or orange larvae that are soft and slug-like.
The larvae are voracious feeders, devouring the lower leaves first and moving upward on the stem, for up to 24 days. Then, they burrow in the earth to pupate in a cocoon of soil reinforced with saliva. In about 20 days, they emerge as adult beetles and continue to feed until winter. Unfortunately, more than one cycle can occur throughout the year.
Partially chewed leaves are often the first sign that the beetles have found your garden! Left unchecked, the beetles will rapidly defoliate the stem. Beetles and their larvae may also chew on the flower buds. A defoliated lily, might not have enough stored energy to bloom or return the next year. All types of lilies may be eaten, but some sources report that some Oriental lilies may be more resistant.
Sometimes, the first evidence of lily leaf beetle infestation is sticky brown frass (feces) containing larvae on leaves. The larvae remain in the frass for protection from the sun and predators.
The larvae are voracious feeders, devouring the lower leaves first and moving upward on the stem, for up to 24 days. Then, they burrow in the earth to pupate in a cocoon of soil reinforced with saliva. In about 20 days, they emerge as adult beetles and continue to feed until winter. Unfortunately, more than one cycle can occur throughout the year.
Partially chewed leaves are often the first sign that the beetles have found your garden! Left unchecked, the beetles will rapidly defoliate the stem. Beetles and their larvae may also chew on the flower buds. A defoliated lily, might not have enough stored energy to bloom or return the next year. All types of lilies may be eaten, but some sources report that some Oriental lilies may be more resistant.
Sometimes, the first evidence of lily leaf beetle infestation is sticky brown frass (feces) containing larvae on leaves. The larvae remain in the frass for protection from the sun and predators.
Red lily beetles are fast and tough to catch. An adult that senses danger displays a defense mechanism, by becoming motionless, folding up and falling with its black underside facing up, making it difficult to see on the ground.
Many people have chosen to forgo planting lilium altogether, but if you are determined to have lilies, you must be diligent about hand picking and crushing the eggs, larvae and beetles at least every few days. Instead of crushing, you may knock the beetles into a dish of hot soapy water. When removing the frass covered larvae, tight fitting throwaway gloves are recommended. Inspect stems and leaves from all angles as the beetles are good at hiding!
Products containing neem oil can kill very young larvae and repel adults without comparable harm to other insects. Spray coverage must be heavy and complete. Neem products should be applied every 5 to 7 days throughout the early summer.
Spinosad, an insecticide made from soil bacteria, is also effective if applied weekly, However, spray in the evening when bees are not foraging as this insecticide is toxic to bees and other insects. Also, don’t spray on windy days as the spray may drift onto nearby flowers.
A natural alternative alleged to help is sprinkling food grade diatomaceous earth at the base of the plant. When the red lily beetle walks through the powder, it is said to kill them in 24 hours. You must reapply after rain. Also, wear a dust mask while working with Diatomaceous Earth. It can be bought in whole food stores.
Recently, parasitic wasps are being released experimentally to keep lily leaf beetle populations in check. “Scientists at the University of Rhode Island have released several species of these predators in RI, MA, NH and ME. Over time, lily leaf beetle populations have declined in most of the test areas and the wasps are gradually spreading into neighboring towns. Hopefully this ecological approach will put a dent in the problem.” (https://blog.longfield-gardens.com/how-to-control-red-lily-leaf-beetles/)
Lastly, you could try using your cordless hand vacuum to simply "suck them up" before they have a chance to escape!
In my opinion, growing lilies is worth the effort it takes to hunt down the red lily beetle. Lilies are so majestic in the garden and their fragrance can’t be matched!
Additional Sources: https://en.wikipedia.org/wiki/Scarlet_lily_beetle
Many people have chosen to forgo planting lilium altogether, but if you are determined to have lilies, you must be diligent about hand picking and crushing the eggs, larvae and beetles at least every few days. Instead of crushing, you may knock the beetles into a dish of hot soapy water. When removing the frass covered larvae, tight fitting throwaway gloves are recommended. Inspect stems and leaves from all angles as the beetles are good at hiding!
Products containing neem oil can kill very young larvae and repel adults without comparable harm to other insects. Spray coverage must be heavy and complete. Neem products should be applied every 5 to 7 days throughout the early summer.
Spinosad, an insecticide made from soil bacteria, is also effective if applied weekly, However, spray in the evening when bees are not foraging as this insecticide is toxic to bees and other insects. Also, don’t spray on windy days as the spray may drift onto nearby flowers.
A natural alternative alleged to help is sprinkling food grade diatomaceous earth at the base of the plant. When the red lily beetle walks through the powder, it is said to kill them in 24 hours. You must reapply after rain. Also, wear a dust mask while working with Diatomaceous Earth. It can be bought in whole food stores.
Recently, parasitic wasps are being released experimentally to keep lily leaf beetle populations in check. “Scientists at the University of Rhode Island have released several species of these predators in RI, MA, NH and ME. Over time, lily leaf beetle populations have declined in most of the test areas and the wasps are gradually spreading into neighboring towns. Hopefully this ecological approach will put a dent in the problem.” (https://blog.longfield-gardens.com/how-to-control-red-lily-leaf-beetles/)
Lastly, you could try using your cordless hand vacuum to simply "suck them up" before they have a chance to escape!
In my opinion, growing lilies is worth the effort it takes to hunt down the red lily beetle. Lilies are so majestic in the garden and their fragrance can’t be matched!
Additional Sources: https://en.wikipedia.org/wiki/Scarlet_lily_beetle
I don't really like to kill bugs; but I make an exception for red lily beetles.
~Me
~Me