How are gardeners dealing with red lily leaf beetle?

July 19, 2016
red lily leaf beetle

Image courtesy Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

by Connie Oswald Stofko

Here’s a question from a reader:

“My Asiatic lilies were attacked by the lily beetles last year.

“This year they (the red lily leaf beetles) are back in my garden. I literally pulled about 6-8 of my lilies and just tossed them out because they were so bad and distressing me– I even tossed out the soil around them. I still have some beetles and twice daily, I go out and look for them and catch about 14 a day. They also have been attacking my gorgeous dwarf Oriental lilies which I’ve had for 6 years and were reliable good performers, except this year. Am on my wits end. What to do?

“I’ve tried spraying with mixture of water, dish detergent and baking soda; also tried Listerine but nothing works.

“I live in Getzville, town of Amherst. I had given some of the babies to friends a while back — they live in Clarence but they don’t have the infestation. Am really baffled.

“Anybody out there having same problems this year?

“Thanks for any suggestions.”

Connie Cordero

I’m sorry to hear that. Yes, I’ve talked to gardeners who are having trouble with the red lily leaf beetle.

The red lily leaf beetle is a problem for true lilies that grow from a bulb. They also attack fritillaria, a spring bulb that some gardeners like. These pests aren’t a problem for daylilies, which aren’t true lilies and grow from a tuber.

Since you had trouble in the past, you might have started a preventive pesticide program around May 1 before they appeared. That advice comes from John Farfaglia, extension educator with Cornell Cooperative Extension in Niagara County. This factsheet lists pesticides you might use.

However, according to the Cornell factsheet, you can’t use pesticides on plants with open flowers, so it’s too late to use pesticides. (The pesticides might kill pollinators that visit the open flowers.) Farfaglia notes that even organic pesticides, such as neem oil or pyrethrum, can kill pollinators when used on plants with open flowers.

If you wanted to use pesticides, you’ve missed the timing for this year, Farfaglia said.

The factsheet says it’s hard to handpick the adults because they are fast.

It does mention that one alternative is pulling out your lilies and planting something else instead. I know that’s sad to hear, but it’s an alternative that some gardeners may choose.

It appears that the red lily leaf beetle is becoming more widespread, Farfaglia said. He’s hearing from more people who are seeing for the first time this year, and for a few, it’s the third year they’ve been dealing with this pest.

“Until some natural control comes along, I don’t think there’s anything that will make it easier for gardeners” dealing with this pest, Farfaglia said.

However, if you do find something that works for you, he would love to hear about it. You can contact Farfaglia in Niagara County or contact the Cornell Cooperative Extension in your county.

You can also share your experiences with the red lily leaf beetle by leaving a comment below.

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12 Responses to How are gardeners dealing with red lily leaf beetle?

  1. Julie on July 19, 2016 at 4:12 pm

    Neem oil works great. Apply every two weeks fir maximum benefit. Apply in early morning or late evening, so that you do not injure bees.

  2. Susan on July 19, 2016 at 4:14 pm

    Once the lilies are gone, I think I would spray the stems and soil with neem oil so that you kill the eggs. I used neem oil this early in the spring when I found my first few bugs and haven’t had any problems since.

  3. Connie on July 19, 2016 at 4:28 pm

    Julie, as I understand it, it’s the time of year, not the time of day, that matters when applying pesticides to lilies. You can’t use pesticide once the plant has flowers. That’s why you could use pesticide at the beginning of May, but not now. The chemicals can be in the flower and can harm bees and other pollinators, no matter what time of day you apply it.

  4. Julie on July 19, 2016 at 5:20 pm

    Here’s an extension reference stating that neem oil is safe for bees, no qualifiers : http://npic.orst.edu/factsheets/neemgen.html

  5. Barb on July 19, 2016 at 5:52 pm

    I had the lily beetle last year in Hamburg. I did the early spring pesticide routine. I drenched the lilies when they were about 2-3 inches our of the ground. I admit, I did it probably 3 times over the course of the spring. I have seen maybe 5 total beetles all season, and the lilies that I had cut to the ground last year because they looked so awful have come back. They will not have as many blooms this year, probably because they didn’t have much time to recharge the bulb before I cut them. Of interest, I had 1 lily in a mixed bed that included Toad Lily. I have found the beetle on the toad lily, feeding, this year. Minimal damage to leaves noted, and I am inspecting daily. Plan to drench the whole bed and all the other lily’s again next year as a preventative. It’s devastating to wait all season to see the holes, the discolored leaves, the weak flowers. It isn’t just the red beetle to look for, also look at small black/brown globs that at first look resembles a slug. That is the worm, covered in it’s own feces that is eating and will drop to the ground to do what ever it does, and comes out as an adult beetle. Important in the spring to douse the ground around the bulb which kills the grubs. Awful pest…

  6. Julie on July 19, 2016 at 6:25 pm

    Here’s my reference fir applying in late evening or early morning: http://ipm.ucanr.edu/TOOLS/PNAI/pnaishow.php?id=53

  7. Elizabeth on July 19, 2016 at 6:38 pm

    We saw these beetles arrive for the first time toward the end of May on our Asiatic lilies. We were watching for them because of the great info posted in this newsletter earlier this year, and we went after them aggressively. We both hand picked and used a spinosad spray. We sprayed in the evening after the pollinators went to bed, and we made sure there were no blooming plants nearby. We sprayed twice, about a week apart, hand-picking in between. They did not return after that and our lilies bloomed beautifully later in the summer. Maybe we were just lucky, but this seemed to work for us. I should add that we only were dealing with a small patch of lilies, maybe 3×5 feet across. Doing this for a very large patch might be daunting.

  8. Donna on July 19, 2016 at 7:45 pm

    Commenters had good advice too.

  9. Brian S. on July 19, 2016 at 10:12 pm

    I have 2 large patches of tree lilies & an area of mixed lilies. I noticed a few holes in the leaves just as many of them were starting to bud. Full infestation of beetles,larvae & eggs. With a little digging I found out about Spinosad a naturally derived insect control. Harmless to bees when it dries. So I marched down to the local hydroponics store grabbed a bottle of Captain Jack’s Dead Bug Brew. Mixed as directed put in a sprayer & soaked the plants. Next day dead bugs!!! Two weeks later light infestation. Repeated application. 3+ weeks a ton of blooms,100s of bees & no bugs so far.

  10. Elizabeth on July 19, 2016 at 10:24 pm

    Brian, that is the product we used, too! I wanted to add that we bought the concentrate and used a pump sprayer, since you have to drench both the top and underside of the leaves for the application to be effective. Much easier than trying to get the spray bottle to work upside down.

  11. Connie on July 20, 2016 at 12:01 pm

    Julie, I checked with John Farfaglia of Cornell Cooperative Extension and he generally supports what you say. He checked the label of a neem oil product, which does list it as a hazard for bees, but only if there is direct contact. If you don’t spray it on the bees, the neem oil is safe. You can spray it at times of day when bees aren’t around, which is very early in the morning (maybe too early for many people) or at dusk. Neem oil is very safe to use (as long as you don’t get it on the bees) and doesn’t leave a harmful residue like many pesticides do. He notes that even spraying soapy water on bees can clog their breathing pores and kill them. So the important thing is that you can use neem oil safely; just don’t use it when bees are actively visiting, and always read the label to find out about precautions. Thanks for your helpful comments!

  12. Julie on July 20, 2016 at 3:56 pm

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