Had damage to your lilies? You might have a new invasive bug called lily leaf beetle

red lily leaf beetle
Image courtesy Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

by Connie Oswald Stofko

Margaret Raupp, coordinator of Open Gardens, alerted me to a couple of problems with disease and pests that she noticed while touring the gardens.

We’ll talk about the first one, lily leaf beetle, today.

Raupp said that when she visited an Open Garden in Lockport, the garden of John Taylor and Mary Brennan-Taylor, almost all of the Asiatic and Oriental lilies were lost to the lily leaf beetle, an invasive species that’s fairly new to Western New York. After she visited that garden, Raupp found it in several other gardens where the gardeners didn’t even know they had it.

I checked with John Farfaglia, extension educator with Cornell Cooperative Extension in Niagara County, who said he started getting calls about this bright red bug last year.

“In some cases, it does a pretty good job chewing leaves,” he said, “and some people report that the flower buds were chewed, too. Just a few beetles can do a lot of damage.”

These insects are a problem for true lilies that grow from a bulb. They also attack fritillaria, a spring bulb that some gardeners like.

The bugs aren’t a problem for daylilies, which aren’t true lilies and grow from a tuber.

If you had lily leaf beetles this year, expect to have them next year, Farfaglia said. If you didn’t have them, look for them in early spring.

The bug is large enough that you will be able to see it, and it’s bright red with black legs, so this is a problem that’s fairly easy to diagnose.

According to a Cornell University factsheet, both the larvae and adults feed on the leaves and flower buds. This doesn’t kill the plant, but it ruins the flower, and of course, who wants to grow lilies if you don’t get the pretty flower?

There are two things you can try to get rid of the lily leaf beetle. One is picking them off by hand, which is hard to do, and the second is using a pesticide, which you can’t do until next spring.

It’s hard to pick off the adults because they move so fast, and the “larvae are disgusting and difficult to hand pick,” according to the fact sheet. If you want to try to get rid of the adults by hand, the sheet recommends holding a jar of soapy water underneath the branch that has beetles. The beetles tend to drop from the branches when disturbed, so your goal is to catch them in the soapy water as they drop. Wait a few hours before dumping out the soapy water to make sure they have completely drowned.

If you want to go the pesticide route, don’t try it now, Farfaglia said. You have to catch the insect in the early stages before the damage is done.

“If you catch them early, one treatment with pesticide at the right time should head them off,” he said.

The larvae hatch in late May to early June. That is the most destructive stage.

Because the lily leaf beetle is rather new to the state, few pesticides are registered for use, according to the factsheet, but it lists some pesticides that could be used.

Do not use insecticides on plants with open flowers; you don’t want to kill bees and other pollinators. This is another reason not to apply pesticide now.

The factsheet adds this lake-friendly tip: Choose the right plant for the right place. Since these beetles attack only lilies that grow from bulbs and fritillaria, consider replacing your lilies with other perennials that aren’t affected.

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21 Comments on “Had damage to your lilies? You might have a new invasive bug called lily leaf beetle

  1. I live in Avon, NY (just south of Rochester) and have battled red lily beetles for at least 3 or 4 years. While handpicking the beetles is possible, it is tedious and requires daily surveillance. Once the larvae appear, (and they do far more damage than the beetles) they are nearly impossible to eliminate. They can devour an entire lily stalk in a day or two.
    I’ve removed most of my lilies or they have simply disappeared because the bulbs don’t get sufficient nourishment due to defoliation. This is one nasty (but cute) little bug. They’ve been spreading westward, so it looks like they have now made it to the Buffalo area.

  2. Try neem oil on red lily beetles. Mix 1 tsp neem oil with 1/4 tsp dish soap and 1 qt of water in a spray bottle. This is a systemic solution which means that it is absorbed into the leaves which kills the beetles when they eat them. It needs to be reapplied about weekly late in the day when the sun no longer shines on the lilies.

  3. Neem oil is one of the pesticides listed in the Cornell fact sheet. Please read the label and follow the instructions when using.

  4. The Cornell factsheet said the lily leaf beetle was discovered in Mooers, NY, near the borders of Vermont and Quebec, in 2002. I guess they’ve been making their way south and west. Thanks for the report from the Rochester area.

  5. My irises foliage lap pear to have a similar round brown spits on them. Is this a marking of parasite damage?

  6. I’ve had the red lily beetle for three years here in Wyoming County outside of Warsaw, and I know I’m not the only one.
    It has wiped out my Tiger lilys-there are so many beetles. In one day a complete set of leaves on a three foot stalk can be wiped out on just one plant. I’ve picked them off but I have to many lilies and to many beetles now in my extensive gardens.
    I have a few of them on the Asiatic lilies too, but not as bad.
    I will try the neem oil for next year.

  7. I have bought lily bulbs at the Connecticut Flower event in early April. The salesman who brought the bulbs directly from Holland told me that ‘Bayer Advanced’ “Rose and Flower Insect Killer” and “Rose and Flower Care” were the only products that they had used that had lasting results with red Lily Leaf Beetles. I live in Western Massachusetts, but get your newsletter because I’ve visited the Buffalo Garden Walk with my daughter who lives in the Buffalo area.
    I had lost lily plants due to the red Lily Leaf Beetle a few years ago. I used the spray on the plants the next early spring and then applied the granules to the soil in the fall to attempt to kill whatever was going to live in the soil for the next seasons attacks on my plants. I also applied the granules in the Spring for that season. This year I applied the spray to a few plants early in the season when I saw a Red Lily Leaf Beetle. This whole season I have seen fewer than a dozen of the beetles on the more than 100 lilies that I have planted around the perimeter of my small city property. Because I have purchased most of my lily bulbs at shows and from growers who import bulbs from Holland I was willing to use these products on my lily plants. I use them exclusively on the lily plants. I still have plenty of bees and butterflies in my gardens. I hope this helps someone who does not want to dig up all their lilies, especially if you’ve spent a fair amount money developing a lily garden.

  8. Sharon, for a very specific question like that, you should contact Cooperative Extension in your county. See contact information here. You could also put a damaged leaf in a plastic bag and take it to a locally owned garden center. They have trained staff who can help you identify your problem.

  9. Elizabeth, I’m glad you enjoyed the garden walk and enjoy this magazine! Thanks for telling us what’s happening in Massachusetts and letting us know that the lily leaf beetle can be controlled, even if you have a lot of lily plants.

  10. Thank you so much for posting this article!!! My 6yr old son thought they were ‘ladybugs’. I said no those red bugs were bad since they about killed our lilys :(. We are in North Tonawanda. At least come spring I’ll be more prepared, maybe there’s a way to repost this again next year 🙂

  11. Thank you for this information. I did not see a problem this year. I have only a few of the bulb lilies. I will be checking for problems next year. Please re-post this info next May, if possible. This will remind gardeners to check their lilies and what they can do to prevent extensive damage. Thanks again.

  12. With all the lilies I have, I have been lucky. Our garden club folks were not though with lilies destroyed. I have known of this insect for a while and have been on the lookout.

  13. I never saw red beetles on my lilies, but did see some damage that could be attributed to that bug. I found a small clump hidden in phlox that were all brown. I don’t know if they bloomed even, or if they are dead. I will know what to look for next spring.

  14. Sorry to say but this nasty little beetle has made its way to Calgary, Alberta, Canada. I found them summer 2015, ruined my plants in a very short period of time.

  15. I noticed these beetles last year. This year the plant is growing with no buds. Will they bloom again? And when?

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