Yes, it’s true! I won the war against the scarlet lily beetle, also called the lily leaf beetle (Lilioceris lilii), an insect that greedily consumes the leaves and even the flower buds and flowers of lilies (Lilium), giant lilies (Cardiocrinum) and fritillarias (Fritillaria). leaving them looking like they’d been put through a blender. They used to be my absolute worst garden enemy, the very bane of my gardening existence, but I haven’t seen one in my gardens in 3 years!
And the solution was so simple! I simply pulled up and composted all my lilies and fritillarias! With nothing to eat at my place, the beetle has moved on to greener pastures, notably my next-door neighbor’s place where lilies still abound. I just wish my hammock was high enough off the ground so I could see over the fence and watch as she bobs up and down, squishing and spraying a good hour every day. I’ve already suggested she stop complaining, make a laidback gardener of herself and, especially, cease feeding her enemy, but she insists “it really isn’t all that much work”… then continues to complain.
What is the Scarlet Lily Beetle?
It’s actually quite a beautiful creature: elongated and bright orange-red on the top, with a black head and a black underside. Originally native to Europe and Asian, it was accidently brought to Montreal in 1942 where it seems to have spent a good 50 years acclimating, then suddenly began to spread back in the early 1990s. It is now widely distributed through New England and all of Eastern Canada and continues to spread. If you don’t have it yet (lucky you!), you probably will one day.
Plenty of Tips… That Don’t Work
I tried mightily to control the lily beetle by other means. I even succumbed to methods best described as folk remedies. Here are some of things I tried:
Hand Picking
The most effective method, but… you have to go about it every morning, as early as possible, while the beetle is still a bit woozy (like most insects, it’s often lethargic early in the day). If you start too late, when it’s more active, it has the annoying habit of quickly dropping to ground when it sees you coming and turning on its back to reveal it black underside. It then plays dead, making it almost impossible to see against brown earth.
When you do catch one, you can either squish it in your fingers or drop it into a pail of soapy water (I find squishing to be sensorily more satisfactory, buy perhaps that’s just me). And you have to do the same with the disgusting larvae (they cover themselves in their own feces, just to discourage gardeners, I’m sure!). And also go over each plant leaf by leaf, turning the underside up, so you can see and crush the orange eggs that hide there.
By dint of repeating these actions day after day, the population will eventually decline, but, just when you think you’ve won the battle, the second generation of beetles flies in and you have to start all over. And yes, there is even a third generation at the end of the summer!
If you keep hand picking, you can at least keep your lilies relatively intact, but… what an effort for a just few flowers!
Coffee grounds
I was told that coffee grounds were perfect tool for discouraging lily beetles. Just spread them around the base of your lilies, they said, and the odor of coffee will keep the beetles away. Result: a total flop. Not only did the beetles carry on chewing on my lilies as if I had done nothing at all, but now my beautiful scented lilies all smelled like coffee… and I hate the scent of coffee!
Companion Planting
On the advice of various gardeners and (former) friends, I tried planting garlic, onions, and pyrethrums near my lilies. The lily beetles just laughed at me.
Insecticide Sprays
I think I tried everything that wasn’t either illegal or insanely toxic (like home-brewed nicotine spray, which can kill you quickly and painfully if you accidentally absorb it). The list includes rhubarb leaf spray, garlic spray and hot pepper spray, with or without added soap to make them stick. The results were mostly abysmal. I simply saw no difference.
Neem oil was the most effective spray treatment. By treating every 4 or 5 days, I seemed to get some control. Insecticides that included pyrethrum, a natural insecticide, also worked… for a while. I had to apply them daily for results. Insecticidal soap and dishwashing liquids worked too, but only if they actually touched the insect. And more daily sprays were required.
In all cases, I had to repeat the treatment again and again… and I have other things to do with my life than spraying insecticides. Moreover, I was (and still am) very concerned that I might be killing beneficial insects (such as bees) as collateral damage.
Extreme Cold
I really got to test this one, as I live in a very cold climate. I’d been told that since lily beetles overwinter in the ground, when it freezes to great depths, they’d be killed. Well, if they are, more fly in from somewhere else, as there are plenty of them here after even the coldest winters. Last winter, we had over a week at -22?C (-30?C) and the ground froze solid to a depth of 7 feet (2 m). Yet I can still see my neighbor hand picking lily beetles every single morning, rain or shine.
Hope for the Future
Although I’ve given up on lilies (and fritillaries) for now, I still have hope for the future. There are natural lily beetle predators in its native Eurasia and at least two are under investigation in Rhode Island (which has a massive cut flower lily industry) to see if it introducing them into North America would be appropriate. If so, and if lily beetles went from being a scourge to only an occasional annoyance, I could live with that and would definitely plant lilies again. But that’s still years away.
In the Meantime
Mostly I have simply replaced my lilies (Lilium) with daylilies (Hemerocallis), which, in spite of their name, are not close lily relatives. Their flowers resemble those of true lilies, come in a wide range of colors, and they are easy-to-grow and very hardy (to zone 3) perennials. And long-lived at that! A real laidback gardener plant!
I occasionally receive bonus lily bulbs when I order plants by mail. They go straight into the compost pile. Planting them would just invite lily beetles back into my yard… and I wouldn’t think of offering such a bulb as a gift. There is no one I hate enough to send such a lily bulb to.
No, it’s over for me: I want to enjoy my garden, not work on it constantly. I’ve had it with lilies. Long live the daylily!
I actually am extremely surprised that I have not seen a single beetle this year, and all I did was spray my plants one a week with neem oil like I did in the past. I did start back in early April with the spray. Maybe the wet weekends we have had in NJ this year helped? All my lilies have had no issues so far, and all my plants are very healthy this year.
Maybe that parasitic wasp that was let out to control them has finally gotten to my area.
Very wet here on Long Island also and I spent an hour last night spraying all of my lilies (I have dozens) as we are INUNDATED with these beetles this year. Good luck to you, I hope they don’t show up.
I’ve hand picked and smashed bugs this my third year. I’ve also put coffee grounds all winter. I have probably over a hundred lilies. I’m a senior and I’m tiring of the battle. I enjoyed your story.
Daylilies get invasive! Well, some of them do. It is worse because I can not bear to discard them, so instead continue to move the excess around. Anyway, they are very different from the other lilies. I mean, they are no substitute. Here, the climate, and associated minimal chill is more limiting than pathogens. Few lilies are reliably perennial. Lilies are are uncommon enough to limit proliferation of pathogens.
I have fought the lily beetle battle for 7 years, 7 years creating natural solutions, coffee grounds cinnamon baking soda, i dug up all my bulbs, washed and cleaned the bulbs, replanted in bottom half of a eggshell. added coffee grounds. put the top eggshell, all my lilies and allium plants, to my surprise they broke through the eggshell, they are 6 weeks old now, not one lily beetle came to the surface, not one got to mate, 0 lily beetles this year, all my plants healthier this year. I am hoping many years ahead I can say 0 lily beetles
Note that a new lily beetle predator is wiping out this insect. It has in my garden and no treatment was necessary. https://laidbackgardener.blog/2021/05/17/lily-beetle-survey-share-your-knowledge/
I have noticed a cat bird in my area spending all day eating the lily beetles from my lilies. They still succumbed to the infestation but I was amazed how he was able to latch onto the stems and pick away at the beetles.
The only lilies that survived were an Oriental that blooms late and a Forever Susan that I kept spraying with Neem over the winter (it’s planted right next to my front door so I had easy access to it). Every once in a while I would squirt the soil over it and it did better than the other lilies. My favorite Trogon and Purple Eyes were decimated – even the blooms were damaged this year.
Interesting about the cat bird! When a new insect arrives, local birds often won’t eat it. Then over time, get used to it and start to. If more birds join your cat bird, maybe we can get rid of the lily beetle.
Pingback: What’s Putting Holes in My Plants’ Leaves? – Laidback Gardener
Sorry to hear you had to give up on your lilies. I used coffee grounds and they worked. I circled them around the base of each stem just as the lilies poked through the ground. If it is applied once they are well up, it doesn’t seem to work but if you do it as they come up…it worked perfectly. So well in fact, that I planted an additional 100 or so bulbs. We’ll see. I’m stockpiling coffee grounds in the freezer, wondering if they’ll work once they’ve been frozen and thawed. Another experiment.
You’re very lucky! I tried pouring ground on planting sites early in the spring and wouldn’t you know, but the lily beetles were crawling around on it before the lily stems were even up. They seemed to love the coffee grounds.
Miriam, I live just over the north edge of Buffalo NY. On 3/25/21, while checking a patch of day lilies (have any escaped the buried black plastic boundary that contains their spread?) and the several Asiatic or oriental lilies in front of them (none of which have emerged, yet), I saw movement in last season’s mulch and flashes of bright red… Yep, the red lily beetles had already hatched and were very active, in the mulch. I scrambled to grab and squish two beetles but fear that I missed a third. And that’s only three of who-knows-how-many.
SO, Miriam, these little destroyers hatch and are active BEFORE the lilies they love even send new growth above soil level. GRR!!! Spread the word – more support for your chosen method to eradicate them from the planet!
Pingback: More Black Flowers for a Goth Garden – Laidback Gardener