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.