In early January, at the SE Vegetable and Fruit Expo in Savannah, GA, we set up a microscope and a magnifying glass (the kind you get in a craft store) to look at bud damage in blackberries. Most of the buds that I sampled looked good. http://teamrubus.blogspot.com/2014/01/buds-look-good.html
On Feb 6, 2014 we be looking at more samples at the annual meeting of the North Carolina Commercial Blackberry and Raspberry Association, in Shleby, NC. (Contact Daniel_Shire@ncsu.edu for meeting information). We will be looking at samples collected from our research blackberry and raspberry fields.
You are welcome to bring in some samples from your fields. We may not get to all of the samples, but we will train you to look at your own samples, so you can sample your own fields on a regular basis.
If you want to bring in some samples or prepare samples for evaluation at home, here is the protocol (courtesy of Michelle Warmund, University of Missouri):
cut 3-4 8″ cane sections from a low, mid parts of a main cane and some laterals from the fruiting area
place each group of canes in in a zippable plastic gallon size bag
label each bag with name of cultivar and where the cane was taken from the plant (low, mid, laterals)
store at room temperature for 4-5 days before the meeting.
At the meeting we will cut canes and check for injury symptoms. Dead cane sections and buds will have oxidized and turned brown after storage for 4-5 days in the “zippable” plastic bags. For examples of injury see images below.