The scarlet lily beetle
The Scarlet Lily Beetle is hands down the most disgusting bug that I come into contact with on a daily basis- and I deal with a LOT of bugs. These bright red bugs, if left unattended, have the potential to wreak extreme havoc on a lily crop, leaving flowers unusable and covered in poop. Seriously- so. gross. I thought it would be interesting to do a deep dive into some information about the Scarlet Lily Beetle and how we work to prevent their impact on our farms.
Scarlet Lily Beetle munching on some lily leaves
Background
Scarlet Lily Beetles (Lilioceris lilii) are also known as red lily beetles, lily leaf beetles, or LLB. The lily leaf beetle is found on true lilies (not daylilies) and fritillaries. The beetles can be found on lots of other plants, such as hosta, flowering tobacco, Solomon’s seal, and twisted stalk. Although the beetle can be found eating these plants, they will not reproduce on them. The lily leaf beetle exclusively reproduces on true lilies and fritillaries. The LLB will not affect daylilies.
Originating in Eurasia, the LLB was spotted in Montreal, Canada in 1945. Lily leaf beetles first made their appearance in the United States in the early nineties, likely as a passenger within a lily bulb shipment from Europe. Since arriving in North America, LLB have spread south and wreaked havoc on home gardens and farms. According to researchers at the University of Rhode Island, “Despite (the) availability of several new cultivars, lily sales have declined by more than 50% concurrent with the spread of the beetle throughout the United States”
Life Cycle of the Lily Leaf Beetle
Lily leaf beetles have the ability to overwinter in our harsh Northeastern Climates using organic garden debris as a bedding. The adults usually emerge during the early spring, or when lily leaves first start to appear in local gardens. The beetles immediately start feeding and soon after begin their egg laying cycle- which will not stop until lily leaves are no longer available. Lily leaf beetle eggs are bright orange and usually found on the underside of the leaves. The eggs can mature to be more of a brick red color.
Things start to get really gross once the eggs hatch into larvae. The larvae will cover their bodies with a thick layer of their own feces. During this stage, they can cruise up and down the lily leaves eating the foliage, while leaving a trail of poop in its path- GROSS! You can oftentimes find adult Scarlet Lily Beetles and larvae feasting in the same area. When the larvae have matured they will drop to the ground and create a cocoon out of soil and their own spit. The new adult Scaret Lily Beetles will emerge from their cocoon within 2-3 weeks and will start feeding before finding a spot to overwinter.
Adult Scarlet Lily Beetles can live for many years. According to the Utah State University Extension, a female Scarlet Lily Beetle is capable of laying 250-450 eggs in her lifetime.
The Scarlet Lily Beetle larvae will cover themselves in their own feces to ward off predators.
eradication of the lily leaf beetle
Unfortunately, there is no “sure fire” method to getting rid of this disgusting garden pest. One of the most effective and safe methods to manage this pest is by physically squishing the eggs, larvae, or adults by hand. This job can get incredibly disgusting very fast. Gloves can make the job much easier and cleaner.
Neem has been used against the LLB with moderate success. Other insecticides have shown promise, such as Spinosad. According to the National Pesticide Information Center, “Spinosad is a natural substance made by a soil bacterium that can be toxic to insects. It is a mixture of two chemicals called spinosyn A and spinosyn D. It is used to control a wide variety of pests. These include thrips, leafminers, spider mites, mosquitoes, ants, fruit flies and others.
Spinosad has been registered for use in pesticides by the US Environmental Protection Agency (EPA) since 1997."
Interestingly enough, we may need to look no further than their place of origin. Lily leaf beetles hail from Eurasia, but we don’t hear about them being a massive issue over there…. why not? Scientists have been researching answers to that question. There are a number of parasitic wasps native to Eurasia which keep the population of Lily Leaf Beetles in check. These wasps are actually attracted to the smell of the feces the larvae spread on their bodies. Perfect!
Scientists have started looking at the possibility of using these same parasitic wasps in the United States to see if they will be effective Different species of parasitic wasps have been released in a handful of New England locations, and are showing promising results. I think I’ll do a deeper dive into these parasitic wasps in an upcoming blog.
Have any comments or questions about the Lily Leaf Beetle? Let us know below!
-Karissa
Resources
Scarlet Lily Beetle- Washington Invasive Species Council
Lily Leaf Beetle (Lilioceris lilii Scopoli)- By Ann Mull and Lori R. Spears
Bulletin #2450, Lily Leaf Beetle- Developed by Philip A. Stack, collaborating researcher, Hampden, Maine; with Professor Eleanor Groden and Extension Professor Lois Berg Stack.
Spinosad General Fact Sheet; National Pesticide Information Center, Oregon State University Extension Services- Bunch, T. R.; Bond, C.; Buhl, K.; Stone, D. 2014.
