TRAVERSE CITY — Snow and cold.
It’s definitely one of the snowiest and coldest winters of the 24 years I’ve lived in the area. And, even though it will be a long time before the snow melts and spring gets underway, there’s already a discussion going on about what this winter’s weather will mean to the region’s crops, ornamental plants and forests.
Many have asked me if the extreme cold will kill off the Emerald Ash Borer (EAB) and give Michigan’s ash trees a bit of a reprieve. This may happen somewhat, but I do not anticipate a big die-off of EAB in the immediate Grand Traverse region. Recent research found that temperatures of -10 degrees will kill about 34 percent of overwintering EAB larvae, and -20 degrees killed 79 percent. Due to the temperature-moderating effect of Lake Michigan and our inland waters, much of the northwest “fruit belt” area has not gone below -9 degrees so far. Farther away from the lakes there may have been more severe mortality of EAB; for instance, the Kalkaska area has reached -25 degrees. Even so, that was the air temperature and the overwintering EAB are protected to a degree by the insulating effect of the bark of the ash tree. EAB overwintering lower in tree trunks will also be well protected by the insulating blanket of snow. This winter may slow down the EAB a bit, but I would not count on any big breaks for our ash trees.
Damage to fruit crops and ornamental plants by rabbits is already a big problem this winter. Deep snow cover has allowed rabbits to reach above trunk wraps or over fencing and chew on unprotected bark. I have already lost four young maples and my favorite crab-apple to bunnies. I’m also worried about what is going on down at ground level, as field mice can be very active under the insulating blanket of snow. Years with even moderate snowfall often results in high levels of mouse chewing damage at the base of woody plants; this season’s snow pack is deep and protecting now, and will likely stay that way for several more months of merry mouse munching before we can see the damage caused.
So far, cold injury to the region’s fruit crops does not appear to be a major concern since the fruit growing sites are in areas where temperatures are moderated by bodies of water. The fruit growing areas in southern Michigan have not been so fortunate. Their low temperatures have dipped as far as -25 degrees. In some places injury to fruit buds has been reported. If you are interested in looking at recent weather data, check out the MSU Extension Enviro-weather web site at http://enviroweather.msu.edu/homeMap.php and choose a reporting station. You can also obtain reliable forecast information for your area at this site.
Erwin ‘Duke’ Elsner is a small fruit educator with Michigan State University Extension.