Thursday, January 23, 2014

Assessing cold damage in blackberry and raspberry buds and wood at annual NC grower meeting

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.

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 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 gallon size plastic 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 gallon size plastic bag. The sections from the lower and mid cane are needed to assess potential damage primarily to the canes. We will look at bud and cane damage on the laterals.

Here are some examples of bud and cane damage in West Virginia at the USDA Appalachian Fruit Research Station in Kearneysville, WV. The photos taken by Dr. Fumi Takeda.
Winter injury to blackberries. Plants with shriveled floricanes and primocanes are green and healthy. Photo: Fumi Takeda 
"Bark" scrapped off, showing oxidation of cambial/vascular tissues. Photo:Fumi Takeda

Primary bud is damaged as indicated by necrosis of partially differentiated inflorescence axis. Secondary bud is still undifferentiated, no sign of damage. Photo:Fumi Takeda.

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