The common summer defendant are show up up in northern gardens : Japanese beetle , squash vine borers , tomato hornworms , magnolia scale , brown marmorated stink bugsand , peradventure later this summer , the dreadedjumping insect . It ’s a knave ’s heading . But a new kid — or at least , unexampled to me — is among the most complained about garden pest in 2023 : thescarlet lily beetle(Lilioceris lilii ) .
Also called the lily leaf beetle , these destructive beetles were visualise in Minnesota for the first time in 2020 . A native to both Asia and Europe , the lily beetle has only been spotted in the United States since 1992 . These beetles can fly so they broadcast well and are now a heavy problem in the northeast U.S. They have also been seen in gardens in Iowa and Wisconsin , as well as Minnesota .
What Damage depend Like
As the name imply , lily beetles go after true lilies — members of the genusLilium . They also damageFritillaria , and sometimes damage hostas , hollyhocks , Solomon ’s seal and lilies of the valley , grant to theMinnesota Department of Agriculture . They tend to ignore day lily ( Hemerocallis ) . Most reports of the mallet have been along a line from St. Cloud to Lake City . Initial sighting of the beetle were in Hennepin , Ramsey , Anoka and Goodhue counties .
As both larva and grownup , the beetles chew holes in the main in lily leaves , but they can also damage stem and flower bud . In a dangerous infestation , the plant can be defoliated and die .
Spotting the Beetle
Their bright red color make grownup beetle well-heeled to find . They are a quarter to a one-half inch long , with a bright ruby dead body and a black head . As larva , the mallet are observe for putting their excretion on their back to hide themselves , according to theUniversity of Minnesota Extension .
The beetles overwinter as adult in the garden — in plant rubble or soil . The emerge in spring , mate and each female will lay up to 450 blood-red eggs on the underside of farewell . While the beetle may feed on other plant , lily and fritillaria are the only position they lay egg . After 10 days , the larva hatch and feed on leaf for two to three weeks . In Minnesota , they are most noticeable in May and early June . They then pupate in the soil , before emerging as adults in another two to three weeks . They bung for the rest of the summer , then go underground during the winter .
Dealing with Lily Beetles
If numbers are minor , you may pass - foot lily beetles as you would Nipponese beetles , drop them into a bucket of soapy water mixed with a small veggie petroleum . you’re able to also hand - pick the larva , but their excrement shield cause this an unpleasant task . TheMissouri Botanical Gardenalso paint a picture put a light coloured fabric under the areas where you discern the beetles . When grownup drop to the ground , you will notice them and can polish off them before they winter . As with any pestilence , practice good sanitation by cleaning up dust and inspecting plants for sign of the beetle before putting them in the garden .
Neem rock oil and other insect powder can be used in knockout cases , but please be cognizant that systemic insecticides will harm beneficial worm as well . Because the scarlet lily beetle is a raw pestis to Minnesota , the country ag department requests gardeners report sightings by contacting theArrest - the - Pestwebsite .
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