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Scientists need public's help to stop invasive lily beetle

Print | Comments () Posted by Beth Daley May 29, 2009 07:19 AM

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By Beth Daley, Globe Staff

Take a look at your garden lilies. If you see a gorgeous red beetle on them, get worried.

The beetle is an invasive visitor that has cut a deadly swath through the region’s lilies over the last 17 years. The bugs do not prey on daylilies, which are not true lilies, but can be found on the stalks of Asiatic, Oriental, Easter, tiger, and Turk's-cap lilies.

The beetle (URI)

And they can devour them so effectively you will be left with nothing but chewed up plants. Thousands of gardeners from Maine to Connecticut have stopped trying to grow lilies ever since they were discovered in Cambridge in 1992. The adults, about a quarter of an inch long, look like a skinny lady bug. If you squeeze them, they squeak - a defense mechanism to deter predators. Today, they are in every New England state.

University of Rhode Island researchers have found a possible solution in a European wasp that is a natural enemy to the lily leaf beetle, and about 10 years ago began releasing them in isolated pockets throughout New England. The wasp lays its eggs in beetle larvae, killing them before giving birth to a new generation of wasps. Researchers wanted the wasps to spread enough to establish a permanent population to hold the beetles in check.

The larvae (URI)

And now, the researchers need samples of larvae from the region's gardens to see if the wasps are taking hold.

But it’s not a pretty process. The larvae are very small – and best noticed by the ball of, well, poop, they carry on their backs. This looks like brown blobs on the leaf.

Lisa Tewksbury, a URI researchers, asks people to tear off leaves with the larvae (and their excrement) and mail them to her. She’d ideally like 10-20 leaves from plants, with a few lily leaves thrown in for the larvae to feed on until they get to her lab.

Once there, she’ll dissect the larvae to see if the wasps are in them to determine how far the wasps have spread. She’ll take larvae from anywhere but is looking particularly in communities in and around Wellesley. Mailing instructions below and for more information go to:
http://cels.uri.edu/pls/biocontrol/index.html
INSTRUCTIONS: Please put about 10-20 of the largest larvae you can find (preferably fourth instars: Fig. 2), and some lily leaves into a rigid container with a lid. Please do not add any water; the lily leaves will provide some moisture. Two suggestions for good sturdy containers are cottage cheese or yogurt containers. Label the lid with your name, complete address, and the date that you collected the larvae. Please tape container closed so that the larvae don’t escape! Include your email address and I will send you my results.

Address:
Lisa Tewksbury,
Dept. of Plant Sciences,
9 E. Alumni Ave. Room 210C Woodward Hall,
University of Rhode Island,
Kingston, RI 02881
Phone: (401) 874-2750
email: lisat@uri.edu

tags lily beetles, Lisa Tewksbury, University of Rhode Island