New beetle threatens lilies & fritillarias

Red lily beetle (Lilioceris lilii) on fritillaria (photo by Adrian  Paine)

Red lily beetle (Lilioceris lilii) on fritillaria (photo by Adrian Paine)

The turds on my crown imperial plants were unwelcome, but no surprise. I’d been forewarned that the red lily beetle (Lilioceris lilii) was in the area. Finally, it found my garden and my crown imperials.

For a relatively mobile insect, the beetle was surprisingly slow in its arrival. This native of Europe made its North American debut in Montreal in 1945 and its entrance stateside in 1992, in Massachusetts. Since then, it has spread. Gardeners are on alert for the beetle as far away as the Pacific Northwest since its sighting near Seattle in 2012.

Those turds that I saw actually are turds: the beetle larvae’s excrement, piled on their backs as they feed. Perhaps the greenish-brown slime that hides the red larvae will not make the larvae unappetizing to my ducks or chickens. Those larvae are hatchlings from eggs that adult beetles laid a few weeks ago. After a few weeks of feeding, the larvae will pupate. New emerging adults will feed until making their way to their winter homes in fall. The worst culprits, in terms of plant damage, are the larvae.

There are many ways to skin a cat and many ways to deal with red lily beetles, none of which need involve highly toxic pesticides. Easiest, of course, would be to avoid growing susceptible plants. Mostly, the beetles’ fare are lilies (Lilium species, which do not include daylilies) and Fritillaria species, which include crown imperials. Susceptibility varies among lily species, with Asiatic hybrids the most vulnerable and some Oriental hybrids more resistant. Lilium henryi “Madame Butterfly,” Lilium speciosum “Uchida” and Lilium “Black Beauty” are among the most resistant.

Because I’m already growing lilies and fritillarias, I might opt for the wait-and-see approach, hoping for the chickens or ducks to take care of the problem. Or take the mano-á-mano approach, regularly inspecting plants to pick off eggs, larvae (yuck) or adults by mano. A container of soapy water held under a leaf is useful for handpicking adults, because they drop soilward when disturbed – also emitting a defensive chirp or squeal.

Neem is a relatively nontoxic (to humans) pesticide and deterrent extracted from (you guessed it) the neem tree, in India. It’s effective if sprayed on very young larvae. I have too many crown imperial plants scatted about to spray easily.

Best of all would be to find some natural controls, and they have been found. Three species of parasitoid wasps (Lemophagus errabundus, Diaparsis jucunda and, especially, Tetrastichus setifer) have proven effective. Releases have been made in New Hampshire, Rhode Island, Maine and Connecticut. Come on, New York: Let’s get some parasitoids.

Moving on to another monocotyledonous plant, this one with no pest to speak of: ornamental onions, which also go by their botanical name, alliums. (“Monocotyledonous,” what a mouthful! This refers to the plants’ leaves, or cotyledons, which function either as seed leaves or as storage structures. Monocots are one broad group of flowering plants; dicots, with two seed leaves, are the other broad group.)

Last fall I reported on my planting of Allium giganteum “Ambassador,” which makes volleyball-sized heads of purplish-blue flowers, and A. hollandicum (or A. aflatuensis) “Purple Sensation,” bearing similar flowers in tennis-ball-sized heads. Both are nice plants for flowerbeds; but, as I reported, I wanted to see if they would naturalize in my south meadow.

Early on, this spring, the experiment seemed a success. The broad, green, strappy onion leaves unfolded, drinking in sunlight, before the surrounding grasses and other meadow plants had hardly budged. As warmer weather moved in, surrounding vegetation grew more boldly, soon beginning to get the upper hand on the onions.

Then the onions – the smaller “Purple Sensation” onions – began to bloom. The blue heads were lost, at first, in the sea of dandelions, orchard grass, goldenrod and other plants coming on strongly. But “Purple Sensation” heads evidently weren’t yet at their peak. They came increasingly into focus as the heads continued spreading their starbursts of blue blossoms. “Ambassador,” as I write, has still to show its heads.

Flowers are prepackaged within fall-planted bulbs. The true test will be whether or not the alliums bloom as strongly, or at all, next spring. Perhaps the “Ambassador” bulbs will even multiply, as they have in the less competitive terrain of the flower garden.

This year, my farmden is taking a rest from the Open Days program. But on that same day, May 30, from 10 a.m.  to 2 p.m., I will be offering some of the plants that I cultivate at my annual Plant Sale. I’ll have nutritious and flavorful blackcurrants, white alpine strawberries, cold-hardy passionfruit, two-crop figs and much more. E-mail [email protected] for more information and the plant list.


Any gardening questions? E-mail them to me at [email protected], and I’ll try answering them directly or in this column. Come visit my garden at



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