For Lily Lovers

Most gardeners know how it is with lilies – you have enough; you definitely have enough. And then it’s March and it’s extremely dreary and here – surprise! – is a pile of summer bulb catalogs with extremely yummy pictures of lilies and you think, well, there’s always room for a few more in the cutting garden and they do make such effortless bouquets


And then, in an increasing number of cases, you think: well, nah; the wretched lily beetles will just get these too and make me feel terrible.

Gilles Gonthier

The scarlet lily beetle, Lilioceris lilii, is marching across New England, laying waste to all lilies in its path. Not everybody has them yet, but everybody who does has gone through the same dispiriting sequence: First there are only a couple and you hand pick them and it’s no big deal. Then there are a dozen or two and a combination of picking and neem sprays seems to do the trick. Then it’s many dozen and pyrethrin, and then it aint pretty.

It’s hard to think of anything good to say about these voracious creatures, but there is in fact one Giant Ray of Sunshine: they don’t travel far on their own. Unlike, for instance, Japanese beetles, which can fly considerable distances, lily beetles spread mostly by way of infected soil, and that means control is possible.

Our Lilioceris Strategy:

1. Prevention: No new ones! We don’t buy potted lilies (or fritillarias, their preferred host). When new bulbs arrive, we throw all the packing material in the trash and gently rinse the roots in tepid water if there is soil clinging to them. There shouldn’t be – and haven’t been – any of the oval, yellow eggs, which are deposited on the leaves, but we always check, just in case.

2. Constant Vigilance: overwintered adults are supposed to emerge from the soil in June. We assume ours might be precocious and start expecting them as soon as the lilies come up. I try to stay ever-alert for beetles or signs that they’ve been chewing, and a couple of times a week I scrunch down and look up. Eggs are deposited on leaf undersides and the black larvae tend to stay there until they’ve oozed out to the leaf tips and started chomping inwards. (Ragged leaf tips are a dead giveaway) .

3. Paranoiac Vigilance: They aren’t always on the lilies. Kristi found the very first one we saw on a tomato leaf. Alas, it was not the first one we had, and thus we come to

4. Kill, Kill, Kill:
a) Adults drop from the plants when disturbed, teach yourself to grab upward so they don’t get away. Crush thoroughly or drop in a jar of soapy water.
b) Larvae are disgusting – gooey and black because covered in their own shit, to keep predators at bay ( aint nature grand?), and they do much more damage than the adults. Removing them is unpleasant but easy; just wipe them from the plants with a rag or a glove covered hand. If you start at the base of the stem, wrap your hand around it under the first set of leaves and stroke gently but firmly upward, you can usually get most of them with one or two passes. People who make lewd remarks may be approached with the working hand, which will shut them up in a hurry. Be sure to revisit affected plants frequently, new larvae are likely to show up.
c). Don’t slack off. Many descriptions of L. lilii say there is only one generation per year. Hah! There are at least two, even in Maine.

5. Perseverance Furthers. It’s probably impossible to eradicate them, but our experience suggests you can keep them to small numbers without working too hard. Reducing them to small numbers from large ones does take a season of of all-out war, but after that it’s easy.

6. Oh, did I mention? The price of lilies is eternal vigilance.

Late July Addendum: When it became clear my torn knee would keep me from Maine all spring, I asked Kristi to put some diatomaceous earth on the leaves as well as on the ground ( see comments), and it looks like Peggy is on to something. It didn’t get rid of them completely and it did look horrible; but allied with the stuff on the ground it  kept the population in check until I was back on patrol.

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  • Carol Leighton Said,

    They have finally found their way to northeastern Maine. I live in Surry, just outside Ellsworth. My son bought me two Stargazer lilies two years ago (at Sam’s Club) and last year I battled them all summer long. I have quite a few others as well. Will try some suggestions found on this site this year and if they are not gone, or mostly gone, I’ll get rid of the lilies.

  • PeggyM Said,

    Diatomaceous earth is the cure for these pests, and it works on japanese beetles too.

  • leslie Said,

    Hi Peggy,

    Thanks for the tip, but please tell us more! I can’t figure out how it would work on the eggs and larvae under the leaves. Do you make a solution and use a spreader-sticker? And what do you do about how the stuff looks?

    While waiting to hear, I’m going to try spreading a blanket of de on the ground underneath and near the lilies, to see if that will nail them when they are on their way down to pupate – or on their way up to procreate. Maybe if the surface layer is sufficiently impregnated with de it would work whether rained in or not. Has anybody tried this???

  • PeggyM Said,

    Sorry to be so long replying, forgot about having made that comment and just re-found it today. The dust does look dreadful, but better white dusted lily plants than no lily plants at all. To kill the larvae you have to score a direct hit on each one with the DE in a squirt bottle of some kind. Any larva that you powder real good will not be present the next day. I use a pint honey squirt bottle, having closed off half the hole in the lid with masking tape. The monsoon weather we have had washes the DE right off of course, while not inconveniencing adults or feeding larvae in the least, so every time it has stopped raining i have gone right out with the squirt bottle and reapplied DE to the leaves, and turned each one over to check for adult or larval miscreants hiding on the undersides and individually powdered each one found. I am in hopes that the amount of DE that has been washed down into the soil under the plants will kill the burrowing pupae, and/or kill the adults on the way up again. Soon as the snow melts in March i will powder the soil where the lilies will emerge. Grrrrr. Onward and upward.

  • PeggyM Said,

    P.S. Dry DE powder in a squirt bottle, not a solution or a paste of any kind. Have found i can shoot down japanese beetles right in the air with this. Only fun i have had this summer, i swear. They can still fly a little ways but soon settle and freeze in place.

  • leslie Said,

    Thanks so much for all the followup, Peggy. I LOVE the idea of shooting Japanese beetles in midair, and I’m guessing it’s faster to dust each lily-eater than it is to crush it – to say nothing of less disagreeable.

    But it sounds as though you too are stuck with constant patrol, killing the wretched things one by one and only killing the ones you see… Let’s hope the ground-covering de blanket works!

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