Could these simple tricks keep away red lily leaf beetles?

lilies and red lily leaf beetle
Photo of red lily leaf beetle courtesy Gordon Ballard. Flower photos by Connie Oswald Stofko

by Connie Oswald Stofko

Recently a couple of readers have shared ways to keep red lily leaf beetles from eating their plants. Could these things really work?

I asked John Farfaglia, extension educator with Cornell Cooperative Extension in Niagara County, what he thought of the suggestions. Bottom line: there are no studies on whether these methods work, but they shouldn’t hurt, either.

Diatomaceous earth for red lily leaf beetles

Susan Baker said that last year she had lily leaf beetles on her lilies, and the plants were halfway gone before she realized what was happening. She was told by a bulb grower to put diatomaceous earth on the lily shoots just as they pop out of the ground in April.

“I did this,” she said. “And I continued to add more diatomaceous earth every once in a while to the base of the lily plants this spring. I have no, as in zero, lily leaf beetles.”

Response from Farfaglia: I have seen diatomaceous earth mentioned before as an organic alternative for lily leaf beetles. It’s probably worth trying but I did not find any research studies that evaluated the effectiveness for this pest.

Homemade spray for red lily leaf beetles

Elizabeth from Western Massachusetts made a mixture of ground eggshells and dish detergent and spread it up the leaves of her lily plants. For some of them, this helped deter the beetles, she said

She also used leftover coffee and coffee grounds on them too.

“I have used the poison in the past and it does deter them some, but they keep coming back,” Elizabeth said. (Neem oil, a pesticide, can be used on the larvae of red lily leaf beetles, but don’t use pesticides on plants with flowers that are open.)

This year Elizabeth goes out every morning before 10 a.m. and again in the later afternoon to pick insects off.

“Some of my lily plants are missing a few leaves because it was easier to remove the insects leaves and all,” she said.

“I will keep on fighting with them because I love my lilies too much to give in, and the fragrance later in the summer is worth my time and effort.”

Response from Farfaglia: This is one of several home remedies that have been tried. There are no controlled studies to evaluate the effectiveness, but it seems harmless to try for those that would like to avoid conventional pesticides.

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12 Comments on “Could these simple tricks keep away red lily leaf beetles?

  1. Ann, thanks for sharing your experience with coffee grounds. Cornell Cooperative Extension says that because the lily leaf beetle is rather new to the state, few pesticides are registered for use.
    Check the label to be sure your plant and this pest is listed. Possible products include neem oil, cyfluthrin, imidacloprid, insecticidal soap, or spinosad (Conserve®). Do not
    use insecticides on plants with open flowers.

  2. Last year I used coffee grounds both on the plant and at the base of the soil. It did seem to help however this year the adults were all over the plants in spite of the fact that all winter I have saved my coffee grounds and applied them to the base of the plants. At wits end I decided to try Sevin I was shocked by the results and how well it worked even with just One application. Only once after I applied the sevin did I see any beatles this year and I applied to second application and now reapply every third week. I’ve had beautiful lilies ever since and no red bugs!!!

  3. I used neem oil last year. It didn

    I used neem oil last year.

    I used neem oil last year. My husband and I picked them off and put them in soap water. This year I used coffee grounds and is seems to work.
    Only picked off three beetles.

  4. I had lots of beetles on my lilies this year. I mixed olive oil, dish soap and water…sprayed my lilies and to my surprise, have had very few now. I avoid chemical pesticides.

  5. Jen, yes, we want to be careful with pesticides and use them only when they are needed. Picking these pests off the plant is recommended. We don’t want to kill insects that are an important food source for birds and other animals.

    One thing to keep in mind is that red lily leaf beetles are an invasive insect. They aren’t a native part of our food web.

    Having said that, we also need to keep in mind that pesticides applied to plants that are flowering can kill insects that come to feed on those flowers. We should never apply pesticides to flowering plants.

  6. Bonnie, thanks for that information. According to the Cornell factsheet from 2010, because the lily leaf beetle is rather new to the state, few pesticides are registered for use. Check the label to be sure your plant and this pest is listed. Possible products include
    neem oil, cyfluthrin, imidacloprid, insecticidal soap, or spinosad (Conserve ®). Does Sevin list red lily leaf beetles on the label?

  7. It is unfortunate that people still insist on poisoning insects that feed the birds and other animals that we enjoy sharing the planet with. We are in the middle of an insect apocalypse. Protect yourself from insect-borne diseases, but otherwise live and let live.

  8. I will stick with Sevin dust. I apply it when the lillies are just sprouting from the earth and again if we have had heavy rain. I have seen only 3 beetles this season. We had a storm tonight and the lilies are tall so I will definitely apply when the plants dry out.

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