Category Archives: January

The impact of a deep freeze on the emerald ash borer


It’s bitter cold in the Ann Arbor area and throughout the country; temperatures have been below zero most of the last two days.

One of the things we’re looking for a silver lining in super cold weather is its impact on bugs, especially invasive species like the emerald ash borer that are not used to unusual weather. A story in the The Gazette (Cedar Rapids Iowa) has a description of the effects of extreme cold on these destructive beetles.

In Minnesota, where arctic outbreaks are colder, more frequent and last longer, they do inhibit the spread of the emerald ash borer, according to Lee Frelich, director of the University of Minnesota Center for Forest Ecology.

In parts of northern Minnesota and North Dakota, frequent, protracted cold spells may actually establish a zone in which ash trees can survive, Frelich said….

Citing recent research conducted in Minnesota, Frelich said 5 percent of emerald ash borer larvae die when exposed to a temperature of 0 degrees Fahrenheit. The mortality rate increased to 34 percent at 10 below, to 79 percent at 20 below and 98 percent at 30 below, according to that research.

However, the exposure must last at least several hours to overcome the insulating effect of the bark beneath which the larvae live.

More details on Minnesota Public Radio News, again from Frelich:

I think the forecast temperatures that we will experience in the next several days will cause a lot of mortality for emerald ash borer in MN. Details below–probably more than you need. I looked up the most recent research this morning, because I figured I will get a lot of questions about this over the next week.

Winter mortality for emerald ash borer is definitely temperature dependent. The larvae can supercool to a certain point, but they die if they freeze, and there is variability in tolerance among individual insects. A recent study from the Forest Service (Venette and Abrahamson–see attached) in Minnesota showed that 5% of the insects die at 0F, 34% at -10F, 79% at -20F and 98% at -30F.

The recent study is Venette and Abrahamson, Cold Hardiness Of Emerald Ash Borer, AGRILUS PLANIPENNIS: A new perspective. The abstract:

This study was designed to assess the cold hardiness of emerald ash borer larvae, the
overwintering stage of the insect. We began by measuring larval supercooling points, the
temperatures at which larvae freeze. We found that larvae collected from naturally infested trees in St. Paul, MN between late October and early December had an average supercooling point of -25°C (-13°F). Research elsewhere indicates that when these insects freeze, they die. Our laboratory assessments of cold hardiness were confirmed during field tests. Naturally infested logs were held outdoors in St. Paul, MN (low winter air temp=-28°C) and near Grand Rapids, MN (-34°C) for ca. 5.5 weeks. Approximately 40% of larvae from logs in St. Paul were inactive or brown, both evidence of death; approximately 90% of larvae from logs near Grand Rapids were inactive or brown, compared with the approximately 10% that showed evidence of death prior to exposure or after being held under cool, non-lethal conditions. Overwintering mortality
may help to minimize the damage caused by emerald ash borer in areas with extremely cold
winter climates.

So there you go; the colder the weather, the more of the bugs die.

Image credit:


Hoppin’ Giovanni (Rapini with white beans)

This simple dish of beans and greens comes from Mary Ann Esposito’s Ciao Italia. It’s similar in many ways to the traditional “Hoppin’ John” served for good luck for the new year.

Hoppin’ Giovanni

Wash and chop a bunch of rapini (broccoli rabe). If you can’t find rapini, some other mild green like turnip greens (or even kale) would work nicely.

Mince a shallot fine and saute in a large pan in olive oil until fragrant. Add a few generous pinches of red pepper flakes. Put the chopped rapini into the pan and cook until the greens are cooked through.

Drain and rinse a can of white beans (cannellini). When the greens are cooked through, add the beans and stir. You can add a little more olive oil to the pan at this point if you want to. Stir and then bring back up to heat.

Serve hot. This would go good with pasta.

a2b3 meeting non-summary for Thursday, January 24, 2013 at Eastern Accents

A bunch of folks met for lunch on Thursday. Here's some notes from that meeting.

I asked people how they stayed warm. They dress in layers, use solar thermal heating, wear sweaters, wear hats, huddle under electric blankets, and all manner of good adaptive Michigan behavior.

Some events coming up, each of which features some a2b3 group member. Some details elided in the interests of brevity, click to links for more details.

Already happened: Linda Diane Feldt spoke at Crazy Wisdom about the liver. "The liver is the largest and most critical organ for detoxifying the blood, moving lymph, and processing food and storing nutrients. I'm in awe of how well it functions, and how much it does." About 18 people were at the event.

Friday night 1/24/13 is David Bloom and Friends playing lounge-jazz standards at Chelsea's "Back to the Roots" cafe, details on Facebook.

Thursday 1/31/13 2-8p at Burton Manor in Livonia is ACE '13, the Annual Collaboration for Entrepreneurs. Details on their web site; volunteer opportunities are available which I'm happy to help you track down if you're interested.

Saturday 2/16/13 10a-noon at Eastern Accents is the 4th Death Cafe, led by Merilynne Rush. Notes on the 3d meeting are here with contact info and more details.

Wednesday 2/27/13 from 7pm to 8:30pm in the Multi-Purpose Room is Dan Romanchik about how to self-publish e-books, based on his experience with writing books on amateur radio. Event details.

Thanks to everyone for coming!

Winter 2009 blueberry crop – price report from Frog Holler, Chilean blueberry marketing

From the Frog Blog: Cold weather leads to price hikes (1/9/2009)

Blueberries–now for some good news. Blueberry prices hit rock bottom this weekend. I can't imagine they could get this cheap in the winter. Prices could be as low as $15 per case.

I'll be following the twitter stream of EuroFruit to get more details as well; country of origin might be Chile?

Chilean blueberry campaign expands

Steven Maxwell | 08 January 2009 | Print | Download | Comment | Share

The Chilean Fresh Fruit Association is to expand its blueberry marketing campaign to Germany, Austria and Italy for the first time

For the third year running, the Chilean Fresh Fruit Association is set to promote its fresh blueberries during January and February in the UK, focusing on increasing market penetration and providing support for British blueberry retailers and importers.

more on blueberry pricing from Bellingham (Whatcom County) WA, 12/14/08:

Prices for one of Ehlers other crops, blueberries, was headed in the other direction. The blueberry has been gaining in popularity, and farmers all over the world have been planting more of the crop. The price for blueberries was around $1.50 a couple of years ago, falling to about 75 cents this year.

"There was a bit of a blueberry rush, so there is much more supply now," Ehlers said.

(presumably that's a wholesale price)