Lucerne Moths Visit Cranberry Beds in Wisconsin in Big Numbers

Tim Dittl, an Agricultural Scientist at Ocean Spray Cranberries and a collaborator, discusses recent sightings of the Lucerne moth in Wisconsin. See below for his article:

This spring, I’ve been receiving several reports of moths flying in beds from Juneau all the way up to Vilas Co. While scouting the fields this week I was fortunate enough to be able to take some pictures of the moths and send them off to Phil Pellitteri, our State Entomologist in Madison, for positive identification. Funny thing, they all appear to be the same critter, the Lucerne Moth or Clover Nomophila, Nomophila neartica, a member of the family Pyralidae or snout moths. Although both Cranberry Girdler and Cranberry Fruitworm belong to this same family of moths, the Lucerne Moth has never been recorded as a pest of Cranberry, not yet anyway.

Lucerne moth larvae typically feed on clover, alfalfa, celery, smartweed and grasses and are sometimes referred to as the “false sod webworm.” Well, we certainly have clover, smartweed and grasses in and around the beds and on the dikes. The literature also states that they are common to Wisconsin, sometimes migrating to the far north. Their activity period ranges from April through October.

Identifying characteristics

Adult: at rest, wings are overlapped and hugged against abdomen, giving a long and narrow profile; forewing elongate, grayish-brown with two side-by-side dark oval spots near middle of wing, and another dark bi-lobed spot a little farther out; hindwing much broader than forewing, pale brownish-gray with whitish fringe.

Larvae: head black; abdomen variably light brown to dark gray with bumpy surface and sparse long hairs; thin dark dorsal line bordered by narrow pale strip. See pictures: Adult photo taken by Christine Ellis, Ocean Spray Cranberries.; larval photo taken from the World Wide Web.

Recently, a lot of mowing operations have been taking place on the marsh and this certainly may be helping drive them into the beds. I’m not sure that we’ll see any problems with them feeding on Cranberry this year, but we need to be aware of their presence and be on the look-out for any unusual insect activity going forward. What a strange year it’s been!

Weekly update from the UW Extension Horticulture Team on Insects, Plant Diseases, and Wildlife

Do you want to know what is going on in the fields, woods, and backyards of Wisconsin? The University of Wisconsin Extension Horticulture program publishes weekly updates through the growing season on special topics with regular appearances by Phil Pellitteri of the Insect Diagnostic lab and Brian Hudelson of the Plant Disease Diagnostic lab.

For the weekly update main page, go here.

For the May 5th podcast, go here.

For the May 5th written summary, go here.

–Liz Bosak