Last weekend after giving my talk on gardening for fragrance at the Wenhmam Museum, Elizabeth Hourihan from Carpenter and MacNeille, Yvonne of Yvonne Blacker Interiors, Pat and Leon from Finn-Martens Design, and I walked across the street to the charming Wenham Teahouse. The company was as enjoyable as was the lunch delicious!
The front walkway leading to the Teahouse is bordered by flowering perennials and seasonal blooms. Unfortunately, the Oriental lilies, which I imagine were planted for their welcoming fragrance, were in the process of being decimated by the red lily leaf devil. I began to hand pick the beetles, but then thought better of it…I didn’t want my friends to think I was over-the-top obsessed nor to walk into the dining establishment with squished red lily beetle all over my hands. If you do not vigilantly destroy the adult beetle, their larvae, and eggs, the red lily beetle will destroy all the leaves and buds of your favorite lilies. To my utter dismay, just last week, I saw one on the leaf of my beautiful native Turk’s-cap lily (Lilium superbum).
While at a local nursery, a woman came in asking the salesperson what poison to purchase to spray to rid her garden of the red lily beetle. I never tire of bending people’s ears to let them know that when you spray pesticides in the garden, pesticides of any kind, you are killing not only the pest, but all the beneficial insects as well. With early hand monitoring of red lily beetles, Japanese beetles, aphids, and what-not, you will not have to resort to spraying pesticides. I wrote the following information nearly seven years ago and am only too happy to pass along:
This past growing season the dreaded red lily beetle attacked our lilies. I had heard innumerable reports from fellow gardeners of this nasty import with its voracious appetite for lily foliage and wasn’t too surprised when evidence of them began appearing on several choice Oriental lilies. The adults chew noticeable round holes in the foliage. The growing larvae decimate the leaves and the flower buds. About 3/8-inch in length, the beetles are bright cadmium red with thin black legs. Because they have no known predators in North America and because of their extended egg-laying season, from spring through summer, they are difﬁcult to control. As soon as you see signs of the beetle (be on the lookout as early as the ﬁrst of April), monitor the plants daily. Squash any beetles that are visible. They are quick, and you have to be quicker. Next check the undersides of the leaves for the following three signs: glistening, miniscule reddish orangish eggs (usually, arrayed in a tiny line), their vile black, gloppy excrement, under which is concealed a growing larger larvae, and hiding adult beetles. Destroy the leaves that are hosting the larvae. The only way to maintain attractive lilies throughout the season is by constant vigilance, handpicking the beetles and their larvae in all stages. (Pages 155-156 Oh Garden of Fresh Possibilities! David R. Godine, Publisher).
I would add to the preceeding, that, with early monitoring, you will make a dramatic impact on the life cycle of the red lily beetle, and controlling them therefore does become easier as the season unfolds–but don’t let your guard down–especially if you have, as do we, lilies that come into bloom throughout the summer. When I say “they are quick, so you must be quicker;” the beetles are very devilish and will easily slip out of your hands before you have a chance to squish them. Approach the beetle cautiously (fortunately so, you will often capture two at once, because they are constantly mating). Place one hand under the leaf to catch it, before it falls into the leaf debris at the base of the plant. Once the beetle falls to the ground, it displays its black underside and is very difficult to see to retrieve.