Blackberry Freeze Damage Sample Evaluation in Savannah

Growers and Agents: I will be at the 2014 Fruit and Vegetable Conference in Savannah, GA later this week. Debby Wechsler, Executive Secretary of the North American Raspberry and Blackberry Association is sharing her table space outside of the Blackberry and Raspberry Conference on Thursday afternoon, January 9, 2014.  I will be looking at blackberry bud samples that may be damaged by the cold temperatures over the next couple of days.

Please bring in your samples. I will have a microscope and some sharp scalpels to slice open the buds.

Protocol:

- take samples from laterals that occur at the top, middle and base of the canes. Bring in several buds from each section. 

-place samples in bags, make sure that the samples are labeled with top/middle/base of cane and variety. 

-below is an example of a bud, this was taken last spring so the buds are further along than what you may see in your field. 

-if you are doing it on your own, longitudinal slices are better. I suggest you go out before the temperatures drop and after as well, to see if there are any differences. 

Holes in pruned blackberry canes?

Hannah Burrack may have figured out what is making the holes in pruned blackberry canes. Check out this post:
http://entomology.ces.ncsu.edu/2013/12/bees-in-pruned-canes/

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.

Managing (?) older plantings of raspberries and blackberries

In our raspberry trials in the NC mountains, where raspberries are adapted and are capable of producing good crops, we have seen productivity decline after the 5th year of fruit production. While in the peidmont areas, we see a dramatic decline in the 2nd year of fruit production of raspberries (they are not adapted to the region). Blackberries on the other hand, tend to be more adapted and will live longer in most regions of the state. However, how long they will last is not known. In North Carolina and other states in the Southern US a recent rise in acreage of blackberries occurred in the past few years and as these plantings age, we need to monitor them to determine how long they will be productive both in terms of fruit and profits.

In the southern US, heat, drought, insects, diseases, if not controlled can take their toll on the productivity of a blackberry and raspberry field. Likewise, plant and soil health needs to be monitored in order to provide a plant with optimal nutrition.  Because this is a fairly new industry, we don't have long term experiences with the crop, however, below are a list of things to think about and address as needed as your plantings age.

Observation of annual growth. Growers should keep good records of individual fields and compare productivity from year-to-year. In addition to yield records, the plants health can be monitored by looking number of canes/plant, cane diameter,  and number of fruiting laterals. You do not need to count each of these, but a picture taken at the same spot in the field each year could help you identify any issues.

Diseases and insects. There is a long list of diseases that can negatively impact  blackberry or raspberry plant health.  In fields that are lightly managed, I most often see cane blight and viruses, and borers negatively impact productivity. 

Weeds. Perennial weeds harder to control over time and annual weeds will compete with crop. Both will impact productivity if left unchecked.

Fertility. There is no known long term research for caneberry fertility in the southern US. However, routine soil and plant tissue samples will help you determine needs and adjustments. Tissue samples should be taken each year and sent for evaluation. In NC, samples should be taken after fruit harvested from the plants. Leaves from the 3-5th node of the primocane plant should be taken and sent to NCDA and they will make recommendations for the following season. Keep your records so you can see if there are trends in your fields. Below are the recommended levels of macro and micronutrients.

Yield and prifitabilty. Good yield records for each field should be taken every year. A simple comparison each year will be your most useful indicator of planting productivity over time. Based on a budget developed at NC State University, when a grower is getting $14/flat, a 10% reduction in yield, their returns fall from $6036 to $4359/acre (see blue font below). You can get a copy of this budget and play with the inputs (any boxes that are blue can be edited).  http://ncsu.edu/enterprises/blackberries-raspberries/management/blackberry-raspberry-budgets-pricing/

Estimated Returns per Acre for Commercial Blackberry Production
for Varying Yields and Wholesale Prices per Flat.  Total yield 19,000lbs/acre, 80% marketable, so net of 15,200 marketable lbs/acre.
	Wholesale Market ($/flat)	Marketable Flats per Acre
		1,621	2,027	2,533	3,040	3,648
	$8.96	($8,173)	($7,533)	($6,732)	($5,932)	($4,971)
	$11.20	($4,542)	($2,993)	($1,058)	$878	$3,200
	$14.00	($2)	$2,682	$6,036	$9,390	$13,415
	$16.80	$4,538	$8,356	$13,129	$17,902	$23,629
	$20.16	$9,986	$15,166	$21,641	$28,116	$35,887

Estimated Returns per Acre for Commercial Blackberry Production
for Varying Yields and Wholesale Prices per Flat. Total yield is 17,100 lbs/acre, 80% marketable yield, so net of $13,600 lbs/acre.
	Wholesale Market ($/flat)	Marketable Flats per Acre¹
		1,459	1,824	2,280	2,736	3,283
	$8.96	($8,429)	($7,853)	($7,133)	($6,412)	($5,548)
	$11.20	($5,161)	($3,767)	($2,025)	($283)	$1,807
	$14.00	($1,075)	$1,340	$4,359	$7,377	$11,000
	$16.80	$3,011	$6,447	$10,743	$15,038	$20,193
	$20.16	$7,914	$12,576	$18,403	$24,231	$31,224

Hurricane Sandy Aftermath

Hurricane Sandy southeast of Cape Hatteras, NC, October, 27, 2012. Source: http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2279

As Hurricane Sandy starts to slip northward, there are some things that caneberry growers in NC and adjacent states should think about. First if you are in eastern NC, you may have wet soils. If your soils tend to stay wet, caneberry plants do not like wet feet. I asked Dr. Phil Brannen Plant Pathologist, from UGA, and here are his thoughts on diseases:

"Assuming that drainage is good, long-term saturated soils could still result in root rot from Phytophthora, but I have rarely seen this in well-drained soils.  Assuming that there is a risk, Ridomil Gold SL can be applied through drip tape; phosphonates could be applied foliarly, assuming that leaves are still active.  There would be no harm in either of these actions, and application of a fungicide could provide some breathing room till the soils dry out.  The plantings may be too wet for a tractor and sprayer to enter for some time, so all applications may be delayed (unless drip-tape Ridomil is the preferred route)."

He also mentioned pruning and leaf spots:  "Any open, fresh wounds would be susceptible to cane blight, but there is really limited value in spraying a fungicide days after pruning -- especially if it has been wet for days already (infections would likely have already occurred).  Not sure therefore of the value of spraying for cane blight at this point, but some systemic fungicides may provided limited kickback if applied within a couple of days.  

Relative leaf spots, I suspect we are far enough along towards leaf fall that we would not currently worry about these."

If you are in western NC, and you are growing fall fruiting red raspberries, your season like ours came to an end abruptly today with the snowfall in the mountains. (We pulled the plastic off late last week in anticipation of this storm). We had a nice crop of berries under high tunnels still producing fruit. Most of our early and mid season primocane fruiting cultivars were done, however, Nantahala had a week or so left and Nova had a couple of weeks left. Our harvest crew was not too upset.

The winds have been strong and may blow some of the leaves off your plants. This is a bit early, but in general the plants have finished the majority of their root building for the season and the lost leaves will not impact your plants too much. Winds can also do damage to your trellises and plants may be laying on the ground. Get the plants up and off the ground as soon as possible and as Phil mentioned, hold off on pruning, until you can get a fungicide on.

Those are my thoughts for now. Let me know if you have any particular questions or concerns: Gina_Fernandez@ncsu.edu

Spotted wing drosophila caught dead in its tracks

Ripe red raspberry with dead SWD stuck in the fruit.

This time of year is usually my favorite time to go to our research plots in the mountains. The temperatures are cooler, the humidity is dropping, and the fall-fruiting raspberries and blackberries are ripe.  It is usually great fun to evaluate and taste our advanced material that is in replicated trials in and out of tunnels. Well, this year, it is not that way. We are getting a double whammy this week, it rained 1.6" in 4 days, was very foggy in between rains so fruit was very soggy, even under the tunnels. AND to add a bit more misery to the soggy berry harvest, our current nemesis the Spotted wing drosophila (SWD) was present in all plots with a vengeance. In the photo above, a dead adult was stuck in a ripe fruit. YUK!

We are hopeful that the weather improves so that the rains and fog will not hamper our fruit production next week. SWD on the other hand, is a longer term problem. Fortunately we have a very dynamic researcher working on this insect, Hannah Burrack. For more on Dr. Hannah Burrack's work on SWD, check out her blog. http://ncsmallfruitsipm.blogspot.com/p/spotted-wing-drosophila-general.html

White (grey or tan) drupelets

In the last few days I have had several calls and emails from growers concerned about white drupelets. Here are a few points that I have gleaned from experience and other articles (see links at the end of the post).

• It is thought that this condition is caused by UV radiation and appears when there has been an sudden increase in temperatures.
• Rainfall appears to make the problem worse, with sunlight on wet berries plus high temperatures. (We have had quite a bit rain in parts of NC lately).
• This was thought to be a result of stinkbug damage many years ago. BUT not now.
• Apache shows more of this problem than any other variety, but white drupelets have been seen on most of the Arkansas varieties. 
• Tolerance for white drupelet varies to some extent by grower. Growers that ship berries have no tolerance, while pick-your-own growers can tolerate a few white drupelets (see last point, educate your clientele).
• White drupelet disorder is usually a problem early in the season and then disappears.
• The berries are still edible, they make delicious pies, juice, ice cream...

For more information see

http://plantpathology.uark.edu/Number_15-2010.pdf

and

http://www.raspberryblackberry.com/Webdocs/nabga08-06news.pdf

Estimation of damage from a grower and his daughter

Blackberry shoot about to be dissected

A grower in western NC sent me this information that he and his daughter gathered as part of a math lesson. They used real data from the plants that had been damaged from the cold temperatures in April. I have asked them to follow up with pictures and yield data. I will keep you all updated. I have also instructed some of you to do the same in your fields.

Blackberry Freeze Damage/Production Estimate

Conducted 4/24/12
Frost and Freeze occurred 4/12/12 27 degrees on top of field and 25 at bottom
Randomly selected one Navaho plant and removed every fruit shoot and sliced each fruit bud to determine percentage of live buds at this development stage of Navaho.
Marked the plant to later determine new shoot generation.
Plant utilized was a 3rd season plant ¾ up the knoll and mid field.
Data collected:
107 fruiting shoots on the plant.
10 minutes to remove all shoots – (approximately $3334 of labor to remove shoots per acre)
Average of 6 fruit buds per shoot at this development and time of season (there were 5 open blooms on the entire plant)
340 buds were determined “alive” out of 642 buds examined – 53%
These plants have been under a vigorous fertilization/irrigation regiment following the freeze – to hopefully stimulate new growth.
Observations made:
0 buds were found alive the day after the freeze.
The live buds appear to be the ones that have developed after the freeze. The live buds are small ones surrounding the top dead buds or developed at a lower lateral of the fruit shoot.
It appears that there is a possibility of further new buds to develop at lower tiers of the fruit shoot.
There is concern of deformed fruit on some buds that appear to be “alive.”
Natchez were much further developed and 0 to very very few new buds are being found.
The 1st year harvest Navaho appear to have a more significant new bud development – no data at this time.

If you would like some help estimating your damage give me a call or send me an email. This is not like the 2007 freeze, so any information you can share will help us all learn from this experience.

What to look for in terms of cold damage in blackberry and raspberry plants ALSO SEE POST 4/19/12

Image 1. Bronzed flower buds

Preliminary reports from across the state indicate that temperatures did go below freezing. It was 27 F in Davidson County,  and 29 F near Danville, VA.  To determine if your caneberry plants were damaged, you will need to wait a few hours. Around noon, go out to your field and start looking at your buds. Closed flower buds will show a bronzing on the sepals (green outer layer of flower buds) see an example in Image 1. However, there does not to be any visible damage, you need to look inside the buds.

Image 2. Blackberry flower bud after freeze injury. Note that only the ovaries and the receptacle are blackened. 

Slice the buds longitudinally and take a close look. In 2007 we saw that the male plant parts (anthers) were fine in some cultivars, but the female parts were damaged (ovaries) and the receptacle were damaged. See Image 2.

Image 3. Damage to blackberry buds in 2007, the entire flower, anthers, ovaries and receptacle are blackened, in most of these buds. 

However in some cases the entire bud was damaged as is shown in Image 3. In either case, no fruit will be formed.

In a few days you may see entire laterals wilting as was seen in the previous post. If you see this type of damage, you will loose the fruit from those buds. BUT you should see secondary flush of growth and based on what happened in 2007 you will get up to 70% of a full crop, later. Later in this year, means a normal fruiting season, I hope.

If you have damage, what should you do? With all the dead tissue, there is an increased risk of botrytis.  You should apply a fungicide to help keep the infection level down. Maintain your spring fertilizer regime and keep weeds under control to reduce competition for nutrients.