Scarlet lily leaf beetle
Are you noticing that your lily (Lily spp. and hybrids) leaves and buds have irregular holes or notches in them this year? Look for the scarlet lily leaf beetle (Lilioceris lilii). This insect pest is making its way westward across the United States. Its ¼-inch-long, bright red body with black underside is easy to spot, and both the larvae and adult can quickly defoliate a plant. According to the University of Wisconsin Extension, lily leaf beetles can also attack fritillarias (Fritillaria spp.) and occasionally lily of the valley (Convallaria majalis) and Solomon's seal (Polygonatum spp.).
How to control scarlet lily leaf beetle
Control it by dropping insects into soapy water or smashing them with your fingers. Horticultural oils like neem oil are moderately effective at killing the larvae and repelling the adult, but must be applied early and often (every 5 to 7 days). And know that sprays will kill all insects that they touch, including beneficials and pollinators that you'd like to encourage.
Plant resistant lily varieties to avoid scarlet lily leaf beetles
If the infestation is severe, you may need to pull out your lilies and grow something else in their place. Or try one of these lily varieties, which appear to be resistant to scarlet lily leaf beetles:
- ‘Black Beauty’ orienpet lily Lilium hybrid
- ‘Madame Butterfly’ lily Lilium hybrid
- ‘Uchida’ lily Lilium hybrid
- Henry’s lily Lilium henryii