When will spring arrive??

The concept of ‘normal’ temperatures might be a thing of the past. After record warm temperatures last year, and record cold temperatures this year, tracking degree days is more crucial than ever. A degree day (DD) at its simplest is an average of the daily high and low temperature minus a developmental threshold. As DDs accumulate over the course of a summer, they can be used to predict certain events like bloom, moth flights, etc., regardless of the calendar date. Currently only the thresholds for the cranberry plant are published (lower threshold: 41°F, upper threshold: 85°F). These thresholds are used for predicting the stage of plant growth but only provide a rough estimate for insect development. We are working on determining the specific thresholds for Sparganothis fruitworm and we should have these results ready by the end of the summer (stay tuned!).

So how delayed are we? The DD accumulations calculated from March 1-May 15 for the past 6 years for Tomah, WI (41/85°F thresholds, single sine method, horizontal cutoff) are:

2008 – 369
2009 – 463
2010 – 607
2011 – 354
2012 – 832 (wow!)
2013 – 336

It seems that slowly, but surely, spring is arriving.

If you are interested in calculating your own DD accumulations, the University of California-IPM has an excellent DD calculator available on their website. Scroll down to the bottom of the page, enter your upper and lower thresholds (the default calculation methods are fine for the rough estimate) and click on calculate. You can then either enter your weather data online or upload a file.


Next Tuesday, the Steffan and Zalapa labs will be at the 2013 Cranberry School

From the Steffan lab, Annie, Liz, and Shawn will be discussing results of research projects from the 2012 field season. Juan Zalapa will be updating attendees on his genetics program. The WSCGA will be hosting their Winter Meeting and Cranberry School on January 22 and 23, 2013 at the Holiday Inn and Convention Center in Stevens Point, WI.

Other research highlights from the University of Wisconsin and UW-Extension include presentations by Rebecca Harbut, Jed Colquhoun, Jack Perry, Lisa Wasko-De Vetter, Christelle Guedot, Eric Zeldin, and Patty McManus.

Online Cranberry Integrated Pest Management Tool from Rutgers University

Rutgers University has a great online IPM tool, PestWeb, for cranberry, blueberry, brambles, grape, and peach. The database categorizes information by chemical, type (e.g. herbicide, insect growth regulator), and crop. For instance, if a search is entered for all herbicides, the database reports the list of herbicides along with links to the label information, material safety data sheets and any supplementary material.

–Liz Bosak

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

Steffan Lab at the 2012 Wisconsin Cranberry Growers Association Meeting

In case you missed Shawn and Merritt’s presentation at the 2012 Wisconsin Cranberry Growers Association Meeting, you can check it out on our website!

There is a link on the “Reduced Risk IPM Tactics” research page.
Or click here: Early-season flooding for insect pest control

For more information about the Wisconsin Cranberry Growers Association, visit their website: Wisconsin Cranberry Growers Association  

–Liz Bosak