Help track the lily leaf beetle

Karla Salp
WSDA Communications

Lily leaf beetles mating

Warmer weather and flowers are here and so is the lily leaf beetle! For the second year in a row, the Washington State Department of Agriculture is enlisting help from local gardeners to track this pest. Last year WSDA was seeking to collect the pest itself. This year we need help to track the development, life cycle and spread of this invasive beetle that threatens both homegrown and commercial lilies and fritillaries.

The beetle only recently invaded the Pacific Northwest and we do not know how (or if) its seasonal lifecycle differs from other locations where it has been found. So far, the beetles have been found in Redmond, Bellevue, Renton, Issaquah, and a gardener recently found one as far south as Maple Valley.

With the help of local gardeners, WSDA is hoping to learn:

• When the beetle starts to mate and lay eggs.
• When new generations emerge each summer.
• When it stops reproducing and begins to overwinter at the end of the year.

Confirmed lily leaf beetle sightings as of May 31, 2018

Tracking the precise timing of the lily leaf beetle’s lifecycle will enable researchers and gardeners to know when to start looking for this pest and when different control activities – like releasing our parasitoid wasps – should be implemented.

You can help with this effort by simply scouting your lilies weekly and reporting what you see. WSU Extension and WSDA have created a website where your observations can be easily uploaded, giving us real-time mapping of this pest’s lifecycle. The lifecycle reporting website is located here. You can also find more information about the lily leaf beetle from Washington State University and in a previous WSDA blog post.

WSDA entomologist Maggie Freeman is heading up the lily leaf beetle project. You can email her with any questions about the project at mfreeman@agr.wa.gov.

We wouldn’t be able to understand the life cycle of the lily leaf beetle locally or develop ways to control them without your help.