MAY 2, 2007
by Lynnette Westfall

lily beetleIt is with a heavy heart that I must report that the dreaded Lily Leaf Beetle is alive and confirmed to be in Alberta. Recently, I was contacted by a lady in Airdrie who described in detail the beetle, larvae, and the swift and destructive damage to her lilies, as well as to her neighbors lilies over the past 2-3 years. She related how she handpicked hundreds of beetles last summer and had tried every known organic method of control with no success. She tried to drown them in water and also bake them in a sealed jar left in the hot sun all day, she was disappointed to realize neither control phased them a bit. She also reported that her neighbour had been infested first and had since removed every lily in her garden. Neither of them knew until speaking with me what it was, despite taking samples to various garden centres in the Calgary area asking what it might be. I should also tell you that I have had unconfirmed reports of red beetles and damage to lilies in the Red Deer area, but these people have not followed up with me again.

On May 1, 2007 I received another call from the lady in Airdrie, telling me she had just found 11 adult beetles hiding in a clump of Campanula in her garden. She promptly sent me live beetles via XpressPost in a sealed container, which I then forwarded to CFIA and to Dr. Ken Fry, an Entomologist at Olds College, for identification. I have also retained a beetle, which I have had preserved by Dr. Fry for display so that gardeners may see exactly what they look like and what to watch for in their own gardens. (Note:  as of 2013 the preserved beetle has lost is lustre and no longer resembles the live specimens in my opinion, so it is no longer useful for this purpose.)

This is a serious pest that can and will hide in other plants, but feeds specifically on all parts of Lilies, Lily of the Valley, Solomon's Seal, Potatoes, Nicotiana, in addition to Fritillaria. In a very short time (1-3 days) plants are completely defoliated leaving only a stem with the appearance of a stick in the garden. Adults overwinter among garden debris or just below the soil surface, to emerge in early spring (April) and immediately begin mating. Interestingly, they only lay eggs and develop on Lilies and Fritillaria. Females lay up to 450 bright orange eggs in clumps or irregular rows of up to 10 eggs each on the underside of foliage. Eggs hatch in 5-10 days, larvae emerge and feed for 16-24 days before encasing themselves in a cocoon under soil for 20-25 days, then emerge as adult beetles to begin the cycle all over again, with up to 3 generations per year. One adult female can survive 2 years. The beetles are known to be strong flyers, which allows them to spread easily to neighboring gardens.

The lily leaf beetle is shiny and bright red, contrasting the beetle's black antennae, eyes, head, legs, and underside. (Photo courtesy Reilly's Country Gardens - please visit their web site for photos of eggs and larvae as well ) The beetle varies in length from about 6 to 8 mm. It has a segmented antennae, notched eyes, and two visible indentations on the thorax. The adult is able to produce chirping sounds and may do so when picked up. The larvae look slug or cutworm like, but an orange-brown color with a black head and often described as looking to be covered in ‘poop’. Indeed, they cover themselves in their own excrement to protect themselves. In Canada the government considers this pest as minor, but I assure you no gardener ever infested considers them minor! Effective control and eradication is a must if they appear or they will devour the lily garden in a very short time.

The very best reference I have found for photos of this pest can be found at http://commons.wikimedia.org/wiki/Lilioceris_lilii

CONTROL METHODS:

  • Carefully inspect any new plant material whether it is lilies or something else before introducing it to your garden. Look for eggs, larvae and the beetle. If you are planting new bulbs ensure they are completely free from soil and have been washed. Be careful ordering and purchasing bulbs and plants from areas known to be infested. Ontario and Quebec have reported the beetle since 1945. Some of you may remember an Alert printed in the Alberta Regional Lily Society newsletter (2003) where one of our members reported finding evidence in an order of bulbs received from a well-known Ontario mail order company.  Chances are this beetle was here long before it was actually confirmed! Southern Manitoba has numerous reports of the beetle, tracked by the Manitoba Regional Lily Society.
  • Handpicking the beetles and larvae appears to be the most effective. Larvae do the most damage, so concentrate on them if they are apparent. Make sure they are dead, and do not leave any squashed bugs behind in the garden. Carry a container with vegetable oil, water and soap to drop them in. Beetles spook easily and are known to drop to the ground, with their black belly up which makes them difficult to spot against the soil. Place a light colored cloth or paper under the plants before picking in order to see them when they fall. Hire a kid to pick them if you are heavily infested and offer 10 or 25 cents for every bug caught - they won’t let any escape for money!
  • If the damage is evident but you can’t find the pest, dig just ½ inch below the soil surface around the plant – they are never deeper than that, and be ready to grab quickly when they pop out. Look for the cocoons while your digging too.
  • Chemical controls include Rose & Flower spray, Orthene or dust containing carbaryl (Sevin), methoxychlor, or Malathion. A systemic control would be the best, as the larvae and beetles would then die as they eat and you don’t need to keep applying it. The previously mentioned chemicals are not systemic however, and need to be reapplied every 5-7 days. Cygon is effective as a soil drench systemic but no longer available. There are very few chemical choices in Canada any longer as many have been removed from the market.
  • Organic controls include Rotenone and Neem oil. The gardener I spoke with said pyrethrum (Rotenone) had no effect. Recently (October 2010), I learned from John Rempel of the Manitoba Regional Lily Society that pyrethrum was in fact effective, but must be at least .5% strength.  Any product containing this strength of pyrethrum will be effective he assured me.  Safer's End All was suggested and is commonly available, although the label states .2%, buy the concentrate and mix it double strength.  Neem oil is very effective according to an internet search, but only kills larvae when it contacts them, so you must spray them directly and be vigilant about it. It only repels the beetles, forcing them to move on.  People I have spoken to say it was an expensive option that did not work at all.
  • This email was received from Dawn Leggett, who resides in Ontario where the beetle has been present for many years already.  She has a very simple solution for you, please read on: 

Hi-
In the May 2011 issue of Garden Central, I read Mary Louise Miller's request for help fighting lily beetles.  My good friend Bill taught me how to deal with them: TALCUM POWDER. Yup, ordinary talcum powder. Baby powder with talc, not with cornstarch, works very well. I buy the largest size and poof it beside the lilies and on the ground around them. I begin in the spring with the first sign of growth, then apply it regularly afterwards. It works on all stages of the beetle. It is cheap, safe for humans and plants, is biodegradable and works. I think it suffocates the critters because it is such a very fine powder.  It also works on ant hills. Just cover the top of the hill and block the entrance to the nest. Hope this idea helps restore lily plants and sanity to those trying to enjoy these glorious plants.

For more information please visit the links listed below:

http://www.umassgreeninfo.org/fact_sheets/defoliators/lily_leaf_beetle.html

http://www.uri.edu/ce/factsheets/sheets/lilyleafbeetle.html

http://www.uoguelph.ca/pdc/Factsheets/Insect/LilyLeafBeetle.htm

http://www.rcgardens.ca/factsheets/factsheets/neem.html

http://lilybeetletracker.weebly.com/

Thanks for reading, and please keep your eyes open for this pest!