Lincoln County Extension Agent Daniel Shires and his summer intern Abby Whitaker are monitoring flower to fruit development at a blackberry farm in Cleveland, NC. They took pictures of 5 flowers of Ouachita (101-105), Von (201-205), Navaho (301-305), Osage (401-405) and Natchez (501-505) flowers when they were at full bloom on 5/21 (left image), then went back on 5/29 (right image) and took pictures of those same flowers/fruit. They will be returning on a regular basis so we can find out how long it takes each of the flowers to ripen fully.

Cane damage, what to do?

Protecting blackberries from winter cold with straw mulch. Photo credit: unknown at this time, will update when I figure out its origin.

This year we have seen damage to canes and buds....here are some suggestions on how to manage the crop for this upcoming growing season.

If you have CANE Damage:
First, determine extent of the injury to your canes.

If canes are completely killed to ground, remove them as they will be sites for disease infection. Once they are removed, you will need to manage the emerging primocanes. There will likely be lots of them and they will grow quickly.  Tipping may be needed more frequently.

If canes are damaged on the upper portions, remove the damaged portions, as they will be sites for disease infection. This is of course dependent on if you have labor and how much time it will take to remove the damaged portions of the cane.

If canes are damaged in spots, the plant will have reduced capacity to provide nutrients to the developing laterals, because of damage to vascular tisse (see figure 3 in the previous blog post). I talked to Dr. Bernadine Strik. OSU Berry Crop Extension Specialist,  and this was her suggestion:
" If canes or the bud base are damaged and there is lateral growth, these laterals may “collapse” – grow well and then wilt. While it’s hard to deal with bud base damage, if there is partial cane damage, foliar fertilization to support lateral growth with the cambium of the cane has time to repair can work. We have resisted putting specific recommendations of foliar feeding during delayed dormant and fruiting lateral development stages, because it would be possible to do “too much” and burn the young leaves. This would  be a concern. Also, foliar feeding will not “solve” problems with poor bud break or “fix” canes that are damaged. It’s not a miracle cure. With that said, if there is partial cane damage and the cane is thus limited on translocation of mobile nutrients, foliar feeding would help get  the laterals through the early development period. I would recommend a low foliar rate of N (e.g. 5% urea) as well as Ca. It’s hard to mix Ca with K, but K might be needed also (caution on not applying too high a rate as this will burn leaves). I would apply a foliar every 2 weeks until first bloom."

For management of diseases, make sure you stick to the recommended spray program and watch out for grey mold (botrytis).

Bud Damage:

We have had this occur in the past, both in 2007 and 2012. If only the primary buds are killed, there may be fruit produced from secondary buds. Here are some links to previous posts regarding bud damage:

http://teamrubus.blogspot.com/2012/04/freeze-2012-field-visits.html

http://teamrubus.blogspot.com/2012/04/cold-weather-and-blackberry-and.html

Crop Phenology Revisited

It has been a cool spring, but the buds are finally breaking. Now is the time to find that notebook with last years key dates of things happening in the plants growth, also known as phenology.  Some of these events are bud break, bloom, primocane emergence, and harvest.

I posted a longer discussion on phenology last year. Here is a link to that site.


http://teamrubus.blogspot.com/2012/04/crop-phenology-when-things-happen.html

RCA trellis with covers

RCA trellis with rowcover, Piedmont Research Station, Salisbury, NC. Photo: K. Snider. 

Blackberry canes with emerged buds, under rowcovers. Photo: K. Snider. 

At the Piedmont Research Station in Salisbury, NC, we have a set of four RCA trellises oriented  North/South and East/West. The primary objective of this project is to evaluate attributes of fresh blackberry fruit. We are most interested in the level of sun scald based injury to fruit based on canopy orientation.

However, the RCA trellis is used in colder regions of the country as a way to grow varieties that are not cold hardy. In North Carolina, twice in the past decade, we have experienced low temperatures (8 April 2007 and 12 April 2012)  that have resulted in significant crop loss. Developing flower buds and therefore the blackberry crop were killed by late season frost/freeze events. So, we are looking at this trellis system as an option for protection from cold in NC.

Temperatures at the Piedmont Research Station in Salisbury, NC, for the have been cold, 20F on 21 March. We had emerged buds so we protected blackberry plants under rowcovers. Although the buds would likely have survived, we wanted to protect them, just in case. We have data loggers recording temperatures under the covers and will download them next time we get to the field and update this post to include those temperatures.

Budbreak 2013

Black raspberry bud 14 March 2013. 

Navaho bud 14 March 2013. 

Prime-Ark 45 bud 14 March 2013

Von bud 14 March 2013

Budbreak on this first day of spring appears to be holding off due to the cooler temperatures we have been experiencing in NC. These pictures were taken at the Sandhills Research Station last week by my student, CM Bradish. Only Prime-Ark 45 is showing any signs of green leaves.

I was looking at the Team Rubus blog post from last year and see that in March (10th), at the CEFS pruning demonstration, blackberry buds were a bit tighter, but not much. http://teamrubus.blogspot.com/2012/03/pruning-workshop-at-center-for.html

No budbreak at this time is a good thing. We have accumulated plenty of chilling and once it gets warm, these buds will grow quickly. We don't need a repeat of 12 April 2012 when flower buds were killed by low temperatures. http://teamrubus.blogspot.com/2012/04/freeze-2012-field-visits.html

If you have time to take some pictures and send them to me (labeled with variety and date photo taken), it would be great to have a snapshot in time from various locations, to see how the crop is developing.

Gina_Fernandez@ncsu.edu

Are you ready for spring?

Andy Rollins,  Clemson Extension Service sent me this image last week. In the circle are some basal buds breaking at the base of pruned cane as well as some buds further up the cane. Daylength, temperature (cumulative and current temperature) and plant hormones are key components that determine when buds on a plant will break.  The daylengths are getting longer, 12 hours and 7 minutes in Clemson SC last week when this was taken.  Chilling hours (cumulative temperatures between 34-45F) is at 325 units, according to one model, however, I think the real chilling is higher (the inception time depends on a temperature trigger of 28F and that first occurred this winter in January). The chilling unit accumulation at the Piedmont Research Station, in Salisbury NC, where some of our research plots are planted is over 1300 units. Daytime temperatures are getting warmer, although they are not staying warm, so continued growth will not occur for a while.

However, spring is not far away. Get pruning done, trellises repaired, irrigation system prepped, winter pesticide applications out (lime sulphur on blackberries has to go out at delayed dormant before buds are 3/4" long). See SRSFC IPM guide for the latest recommendations. http://www.smallfruits.org/SmallFruitsRegGuide/Guides/2012/2012BrambleSprayGuide.pdf