Where Have All the (Lily) Beetles Gone?


Lily beetles are so brightly colored you can scarcely miss them. Photo: http://www.telegraph.co.uk

I usually write this blog to answer other people’s gardening questions, but today I have one of my own. 

What has happened to the scarlet lily beetle (Lilioceris lilii)? I saw very few in my garden last year and none at all this year. In previous years, they were so numerous it really wasn’t possible to grow lilies (Lilium spp.) without applying some method of control.

The bright red insects would normally be hard to miss: they really stand out against green lily leaves, plus the damage they cause, chewed leaves and flower buds, is pretty obvious. 

Reader Rebecca Baker, from Montreal, also in my province, but 250 km (155 m) to the west, reports the same thing.

have seen lily beetles this year, though: in Ottawa, yet another 200 km (125 m) further west. While visiting the Ornamental Gardens at the Experimental Farm, I saw a (yes, just one!) lily beetle and a few chewed on leaves. So, the lily beetle hasn’t entirely disappeared.

The Ornamental Gardens in Ottawa still have lily beetles. Photo: friendsofthefarm.ca

Weather Or???

In all likelihood, this is simply a weather-related phenomenon. We’ve had two very hard winters in a row in North Eastern North America: the winter of 2017-2018 was extremely cold, with frost descending to unheard of depths in the ground. Temperatures during the winter of 2018-2019 were not as extreme, but it came exceptionally early and lasted exceptionally long. Maybe the beetles weren’t able to survive such conditions. 

Tetrastichus setifer parasitzing a lily beetle larva. Photo: Tim Haye, http://www.flickr.com

But there is also the possibility that one of the beetle parasites released to help control the lily beetle have finally kicked in. Various parasites have been introduced in the US and Canada to try and manage the lily beetle, including a parasitoid wasp (Tetrastichus setifer) and an ichneumon wasp (Lemophagus errabundus), as the scarlet lily beetle, of Eurasiatic origin, has no natural predators or parasites in North America. The two predators been shown to be very effective locally and there are signs they’ve been spreading. 

So, I have two questions for readers. 

  1. Have you noticed any decrease in scarlet lily beetle numbers?
  2. If local numbers have dropped, do you have any idea why?

Just click on Leave a Reply at the bottom of this page and let me know. Please indicate where you live: that will give a better portrait of where the lily beetle are thriving and where they are decreasing.

Thanks for your help!

21 thoughts on “Where Have All the (Lily) Beetles Gone?

  1. Lia Lindeman

    Lancaster , Ontario near ON-QC border
    I was super surprized with minimal damage this year. I still killed about a dozen adults and a couple in larva stage of course missed some …they are so fast !

  2. Gabriella Kastelberger

    I ,on the other hand ,have had surprisingly more lily beetles this year in my gardens. They are tenacious, prominent and luckily highly visible so I ‘m constantly on the look out for them. Two of my lilies have been destroyed so far. Hemmingford, Que.

  3. John

    Toronto, Ontario: Two years ago there was hardly a leaf left on any lilies. This year there was ONE beetle late spring; it was quickly dispatched, and have not seen evidence of a single one since!

  4. Vanessa Doell

    They still seem to be going strong in a few spots in my province, Saskatchewan. I have been lucky to have been spared but they are a regular complaint on a provincial gardening page with a high number of complaints coming from a few spots. One of which is the city of Prince Albert and surrounding area.

  5. Angie Weiland

    I live in the Annapolis Valley, in Nova Scotia. Only found, maybe, four or five lily beetles, this year and almost no eggs or grubs. No damage to plants and lovely blooms. Other years, I have spent hours picking beetles, eggs and grubs.
    Perhaps, the cold, open winter did me a favour!

  6. Annette Daigle

    In the past 4 years those beetles killed all my lilies here in Halifax, I planted new ones and I saw a few larva of something eating the leaves but picked them off and killed them and saw no beetles and all my lilies bloomed this year 🙂

  7. Kathy

    Kathy, Uxbridge Ontario. Two years ago I had over 50 that were dumped in soapy water and discarded. This year I have seen 5 at the beginning of the season, that were squished, and that has been it. I have around 20 Lily plants.

    Thank you.

  8. Pat

    Avon, NY just south of Rochester. Some lily beetles in a two waves, but nothing like earlier years. OTH, I have very few lilies left for them to feast on and, while they also attack the fritillaria , there was not nearly as much damage from the larvae this year. It’s possible that, like Japanese Beetle invasions, they are just taking a year off.

  9. Alison

    Have seen *very* few Lily beetles or evidence of their presence (chewed leaves) this season. In past years, spent a lot of time swabbing beetle poop and spraying Neem oil. I garden in Brunswick, Maine.

  10. Patricia Griesser

    I live in Mississauga. In early spring (April/May) I saw only a few Lily Beetles in my garden. Unfortunately they came back with a vengeance by July. I’m at the point of removing all my lilies since I cannot keep on top of them by hand picking.

  11. Chris

    I have had a few but not as bad as last year. Someone suggested I use coffee grounds and I did. After that I saw one but it was only after they had all bloomed.

  12. Barbara Stevenson

    Barbara, Brighton Ontario
    I haven’t seen any this year. Other years they have been eating milkweed plants, along with the monarch caterpillars.

  13. Valerie

    Valerie Annapolis valley Nova Scotia. Last couple of years we had so many I couldn’t keep up with destroying them. This year only 3 all summer. I think it was the harsh winter of 2018

  14. Mari Lise Stonehouse

    Mari Lise, downtown Toronto. I don’t have lilies, but I do have Frittilarias, Melegris Mix . Last year I killed about 20 and this year 4. I thought it was due to the cold wet spring.

  15. Tami

    I noticed that too. I have 26 garden clients and saw 12 at the most. Perhaps our second winter with extreme cold took them out. I’m in southeastern Ontario

  16. Kathy Wong

    Kathy, Calgary Alberta. I have experienced the same thing. A drastic reduction last year and only 2 “kills” this year. I am so thankful for whatever reason they have decided my yard is not a good home!

  17. Jackie

    I have never seen the red lily beetles until this year. They decimated one variety that I have, mildly attacked another three varieties and left all (10 or so) other varieties alone completely. Easily caught over 50 and destroyed plenty of larvae. Hamilton.

  18. 1. I have not noticed a decrease in scarlet lily beetles because they do not live here. (I am in Los Gatos, but that is irrelevant without beetles.)
    2. There are SO many variables that could account for the observed decline to their population. I suspect that the two possibilities that you cite are the most likely. However, there are other naturally occurring pathogens. There might have been an increase in the number of birds who eat the insects. If they are active in the evening, they might be getting eaten by bats.

  19. Monica Bailey

    Bridgetown NS and our lily beetle population was overwhelming this year. The plants were completely destroyed before they could bloom.

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