The most common host plants for the invasive scarlet lily beetle (Lilioceris lilii) are tiger lily, Easter lily, and oriental lilies. Other species that may be targeted and have minor feeding damage includes lily of the valley (Convallaria majalis), Solomen seal (Polygonatum spp.) and several Hosta species. This species has been detected in many of Michigan’s southeastern counties. This lily beetle is between ¼ and 3/8 inch long and the top of their body is red and shiny. The underside is white, and the head, legs, and antennas are black. If they feel threatened or disturbed, they squeak to scare off their predators. Adults overwinter in leaf litter and lay eggs between early spring and June. The orange eggs can be found in clumps of 3-12 on the underside of leaves. The larvae feed between 16 and 24 days and can do the most damage to the plant.
The University of Utah has a great web page with photos of each life stage and damage.
Have you seen this species? Report it to us or on the MISIN website or smartphone app! Please include a photo for ID verification.
Environmental effects
Scarlet lily beetle can defoliate the entire plant and cause damage to stems. The largest threat is to residential gardens. To prevent further spread do not transplant lily species to new properties.
Treatments
There are several treatment options for managing scarlet lily beetle. These include a chemical and non-chemical option.
NON-CHEMICAL CONTROL METHODS
- Hand removing adults: if you have a small number of plants or there is a small population size of scarlet lily beetles, hand removing the plants may be most effective. Place a bucket of water, soap, and a small amount of vegetable oil under the affected plant. Drop the adults, larvae, or eggs into the bucket to kill them. Note: this will need to be repeated several times a week for multiple weeks.
CHEMICAL CONTROL METHODS
- Insecticide (neem oil): neem oil can be sprayed onto the foliage of infected plants. This insecticide is not harmful to pollinators but should not be sprayed onto the flower itself. The leaves need to be heavily covered in need oil and the process need to be repeated after the eggs hatch within 7-10 days. Note: neem oil kills larvae and repels adults. It should be reapplied every 5-10 days.