Cranberries and Climate Change in Grow Magazine

Cranberries were featured in the latest article about the challenges that agricultural producers face in a changing climate. Rebecca Harbut and Ed Grygleski were interviewed about the unusual weather patterns that stressed the vines this past growing season. See pages 3 and 4 of the article for their contribution.

The College of Agricultural and Life Sciences, at University of Wisconsin-Madison, publishes Grow Magazine three times a year, highlighting agricultural research in Wisconsin. The University offers a free subscription, go here for the subscription form. For a pdf copy of the latest Grow issue, Spring 2013, go here.

— Liz Bosak

Cranberry Pollination Research at the University of Wisconsin

In the spring and summer of 2012, Hannah Gaines, a PhD student in the Entomology Department at the University of Wisconsin, did experiments in the field and in the greenhouse to better understand what non-bee factors may be influencing cranberry pollination.

Hannah's cages

Monitoring one of my pollination treatment cages in the field.

Hannah's greenhouse experiment

Hand pollinating cranberry plants in the greenhouse.

Hannah's greenhouse experiment

Hand pollinating cranberry plants in the greenhouse.

To learn more about her work on native pollinators, see this article.

Spotted Wing Drosophila in Cranberry: Is this an Issue?

Here is an article from the Wisconsin State Cranberry Growers’ Association newsletter about recent research in the Steffan lab:

Cranberries and spotted wing Drosophila (SWD) in Wisconsin

Shawn Steffan (USDA-ARS Madison, WI), Jana Lee (USDA-ARS Corvallis, OR), Laura Lavine (Washington State University), Doug Walsh (Washington State University), Chase Metzger (Washington State University), Juan Zalapa (USDA-ARS Madison, WI), Christelle Guédot (University of Wisconsin-Madison), and Phil Pellitteri (University of Wisconsin-Madison).

This holiday season, there will be one demographic that won’t want to eat fresh cranberries: spotted wing Drosophila maggots. Drosophila suzukii, commonly known as SWD, does not appear to like cranberries very much. Following multiple replicated trials using ripe, under-ripe, and over-ripe organic Wisconsin cranberries, SWD females would not (or could not) insert eggs into under-ripe or ripe cranberries. This suggests that healthy, current-year fruit should be safe from attack.

Scaptomyza (Drosophilid)

Among the over-ripe, decaying cranberries (harvested, frozen, thawed, refrigerated) just two eggs were found among many berries, but no mature larvae were detected, and no adults emerged. Fortunately, rotting fruit don’t make it into the harvest because they generally don’t float. Decaying fruit get devoured every spring and summer by other drosophilid flies (see photograph above), various beetles, and countless hordes of mites and springtails.

While none of the SWD larvae successfully developed within the highly acidic flesh of fresh cranberries, studies using physically damaged cranberries showed that SWD could develop to adulthood. Again, these berries represented wounded, decaying fruit, not the sort of berries that would get harvested. That said, SWD populations could build within cranberry beds and potentially play a role in regional source-sink dynamics.

Unfortunately, SWD females love blueberries and raspberries—this we learned early. The good news for cranberry growers is that SWD adults have only rarely been trapped in/near cranberry beds, and in these cases, a blueberry or raspberry patch was nearby.

So, the take-home message: current-year cranberries (that aren’t damaged and/or rotting) appear to be safe from SWD attack. Conversely, last-year’s decaying bounty of unharvested cranberries may be vulnerable. SWD populations will likely be found each spring and summer in fruit-growing regions, but the risk to cranberry production seems minimal.

If you are suspicious of any infested fruit, contact your local Extension agent.

For other fruit crops, here is a list of resources that may be helpful:

University of Wisconsin Extension has released an article on Spotted Wing Drosophila, Drosophila suzukii, with several suggestions for scouting and trapping the fruit flies.

University of Wisconsin-Madison has a website about the Spotted Wing Drosophila in Wisconsin.

The University of Minnesota and Michigan State University have web pages with extensive lists of resources including a map of counties with SWD in Minnesota and Wisconsin.

North Carolina State University’s Small Fruit and Specialty Crop IPM blog

Pacific Northwest Insect Management Handbook SWD page

–Liz Bosak

Update on a Frosty Spring for Fruit Crops in the Midwest

Click here for the latest article from the Wisconsin State farmer discussing this year’s early Spring and cool temperatures. A Michigan State University extension article covers growing degree day accumulations for this Spring and its impacts on grape production. If you’d like all of the gory details of how frost injures plant tissue, then check out Janna Beckerman’s article at Purdue University.

The National Agricultural Statistics Service offers weekly email updates for a variety of crop data including crop-weather data, for more information go here and for Wisconsin click here.

Still want more information, check out this earlier post.

–Liz Bosak

Wisconsin Fruit Crops and Frost Injury this Spring

Recently, Shawn posted an article on the Entomology Department’s website about frost injury to cranberries in Wisconsin, follow this link.

For more information about spring frost injury in Wisconsin fruit crops, go to the University of Wisconsin Extension Fruit Crops website.

Specifically, see Rebecca Harbut’s article on “Understanding Frost in Fruit Crops”. She and Patty McManus have another article on “Impacts of High Spring Temperatures on Fruit Crop Management”.

–Liz Bosak