What causes red drupes?

Red drupe in Prime-Ark 45. Likely due to excessive rain, These drupes never turned black.

Usually all the drupelets on a ripe blackberry fruit are uniformly black. Sometimes the fruit can have drupes that are white, tan or red. White and tan drupelets have been discussed before (https://teamrubus.blogspot.com/search?q=white+drupelet). 

The focus of this post is to discuss the occurrence of red drupes in blackberry fruit. This reddening can occur after and before fruit is harvested.  There are several known causes of red drupes and some conditions that are speculation. No matter what the cause, excessive amounts of red drupes can result in rejection of fruit in wholesale markets.

After harvest

Reversion. This is the most common cause of red drupes.

Symptoms. Drupes are black at harvest and turn red after harvest.

What is known. Research conducted by Max Edgley from the University of Tasmania looked at several factors including nitrogen rates, physical damage during harvest and transportation to the cooler, air temperatures during harvest, slow or fast cooling of fruit after harvest.  

Key Findings from the University of Tasmania study:

• Physical damage (bruising, impact and fruit compression) during harvest and shipping is the main cause of red drupelet disorder
• High nitrogen fertigation during harvest can significantly increase the amount of fruit with red drupelet disorder post-harvest
• Fruit core temperatures exceeding 23C (73F) at harvest significantly increase the amount of red drupelet post-harvest
• Harvest times, techniques, and shipping conditions can be manipulated to reduce incidence of red drupelet disorder
• A step-cooling process reducing the rate of cooling post-harvest has been effective in reducing incidence of the disorder
• They also found that early season fruit is more prone to this disorder. 

https://www.utas.edu.au/tia/research/research-projects/projects/red-drupelets-on-blackberries2

https://www.utas.edu.au/__data/assets/pdf_file/0015/1110435/Blackberry-red-drupelet-fact-sheet-2017.pdf 

Addedum from Alejandra Salgado (PhD U Ark):  a weak cell wall can also cause reversion. 

See also blog post on red drupe reversion here: https://teamrubus.blogspot.com/search?q=white+drupelet


Before harvest

Redberry mite. (Redberry disease).

Symptoms. Fruit that are infected with Redberry mites have drupes never turn black. Red drupes are hard.

What is known. The mites inject a toxin into the base of the drupelets and as a result, the drupelets fail to develop normally.  Redberry mites are uncommon in the eastern United States. If you suspect they are the cause of red drupelets, samples should be submitted to your local plant disease and insect clinic for diagnosis.

Here is more information from:

Utah State University.

https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=2944&context=extension_curall
University of California

http://ipm.ucanr.edu/PMG/r71400111.html 

Excessive rain.

Symptoms. Red drupes are soft and never turn black.

What is known. There have been reports of significant red drupelet in parts of NC this year in fruit that are otherwise ripe and ready to harvest. Many, but not all of the fields have tunnels over them. The cultivar Prime-Ark 45 is seeing most of this disorder this season on the floricane crop. We cannot confirm that the rain is causing the red drupes, it is just our best guess at this time as the above (reversion and redberry mite) have been ruled out.

Viruses?

Red drupes have not been identified as symptoms associated with viruses to the best of our knowledge. 


Authors: Gina Fernandez, Hannah Burrack and Penny Perkins-Veazie and in consultation with multiple experts around the world. 

Red drupelet disorder

Red drupelets in blackberry fruit harvested in the afternoon. Upper image is showing more than 15% red drupelets. Lower image is a mild case. Upper image PPV, lower image GF.

Now that we are reaching peak harvest and peak summer temperatures, red drupelet disorder is starting to appear in harvested fruit. After the fruit is harvested, individual black drupetlets will revert back to a red color. Red druplet disorder is also called reversion, reddening or red cell. Penny Perkins-Veazie has worked on this problem for several years. Here are some of her thoughts:

- Harvest before 10 am, get to cooler within an hour of harvest. 
- Remove heat quickly or delay field heat development.
- Forced air cool may need to be set 5 F higher than usual to avoid excess coldness at top of pallet.
-Semi truck loads tend to have more red drupe at front end (near rig) and at top due to air movement and nearness to cooling units.
-Least susceptible variety continues to be Navaho.  Those showing problems are Natchez, Tupi.  Ouachita can be problematic if rainfall has been high and harvest is going into afternoon.
-I'm not sure about PrimeArk 45 or Osage.  The new 'crispy' type does not seem to get red drupe, indicating a firmness/cell wall component in color reversion.
-A 15% red drupe (color reversion) in the load is considered the limit to avoid rejection.  
-Trellising or using E-W row orientation helps to keep fruit in shade longer, decreases exposure to light/heating.  (GF: our shift/RCA trellises seem to have less red and white druplets in general)
-We are not yet sure of production practice issues on red drupe although some reports with tunnel grown blackberries indicate keeping nitrogen rates lower and avoiding heat buildup help with the problem.
-Environmental possibilities for exacerbating the problem seem to be water stress (high rainfall within a few days of harvest, or high rainfall in spring followed by very hot temperatures), nitrogen imbalance, and possibly calcium/potassium availability.

Max Edgley, from the University of Tasmania, has an excellent slide show on this disorder. Max attended the Rubus and Ribes Symposium last year and has shared some of his findings here:

http://www.utas.edu.au/__data/assets/pdf_file/0003/792363/Red-drupelet-disorder-Presentation.pdf

WInter Caneberry Checklist

Blackberry and Raspberry Seasonal Checklist
Winter 2012-13
Gina Fernandez, Small Fruit Specialist
North Carolina State University

This checklist was originally developed for blackberry growers in North Carolina. Many of the items apply to raspberry production as well. You may have to adjust your work activities either earlier or later depending on your location. For more detailed information, check the Southern Region Integrated Bramble Management Guide and the Southeast Regional Bramble Production Guide at: http://www.smallfruits.org/SmallFruitsRegGuide/index.htm.

Check the items off as they get done. This list is very general, but should help get you to think about what types of activities occur at various times of the year. If you would like other items to be added to this list, send them to me and I will add them next time.

WINTER
Plant growth and development
√ Plant is not visibly growing during the winter months although many blackberries will retain their leaves through the winter
√ Some differentiation is occurring in the flower buds
√ Low chilling cultivars can break bud in January after adequate winter chilling. You can monitor chilling hours accumulated in eight states in the eastern US by accessing this site: http://www.nc-climate.ncsu.edu/cronos/blackberry/index.php

Pruning and trellising
√ Pruning should occur in late winter.  However, in some areas winter ice storms can do tremendous damage to plants and trellis systems. If you produce blackberries in one of these areas, pruning can take place early winter to help avoid severe damage.
√ Make trellis repairs after plants have defoliated but before pruning and training.
Erect types
√ Prune out the spent floricanes
√ Tie canes to wires in a fan shape
√ Cut lateral branches back to 8-12”
√ Thin canes to 6-8 canes/ hill (4 ft spacing)
Trailing types
√ prune out spent floricanes
√ tie or weave canes to wire so that they do not overlap
√ prune side laterals to 12-18”
√ thin canes to 6-8 hill (6-8ft spacing)
Primocane fruiting raspberries and blackberries
√ Prune (mow) primocane fruiting types to ground level

Weed control
√ Many summer weed problems can be best managed in the fall and winter using preemergent herbicides. Determine what weeds have been or could be a problem in your area. Check with local extension agent for cultural or chemical means to control these weeds.

Insect and disease scouting
Check the Southern Regional Bramble integrated Management Guide for recommendations. www.smallfruits.org

√ To learn more about the spotted wing drosoplila and how it may impact your fruit in 2013, check out Hannah Burrack blog, she has lots of links in addition to her blog posts
√ Scout fields for insect and disease damage and remove those canes
√ Remove wild blackberries and raspberries by the roots if they are within 600 ft of your planting during the winter or treat with glyphosphate in the autumn
√ Apply liquid lime sulphur or Bordeaux for disease control before new buds are 1/8”

Planting
√ Take soil tests to determine fertility needs for spring plantings.
√ There are some new raspberry and blackberry cultivars available in 2013. If you have not tried them or it is not know how they will do in your region, it is best to order a small quantity to see how well they will perform in your area
√ For larger growers, prepare list of cultivars for 2014 plantings and order now. Smaller quantities of plants can be order in early 2013 for spring 2013 planting
√ A commercial small fruit nursery list at http://www.fruit.cornell.edu/berry/nurseries/

Water management
√ Make repairs to irrigation system (check pumps, lines, etc)
√ Plants generally do not need supplemental water in winter

Marketing and miscellaneous
√ Order containers for next season
√ Make contacts for selling fruit next season
√ Attend grower meetings:
o The 2013 North American Raspberry & Blackberry Conference Meeting
√ January 27-30, 2013 in Portland OR. http://www.raspberryblackberry.com/local.cfm?doc=webdocs%2FNorthAmericanBerryConference2013.htm
o 2013 SE Regional Fruit and Vegetable Conference
√ Jan 10-13, Savannah GA
http://www.seregionalconference.com/
o The North Carolina Commercial Blackberry and Raspberry Growers Association
√ Feb 19, 2013.  Shelby NC. For more information contact Daniel_Shires@ncsu.edu or Josh Beam <josh.beam@dole.com>

NOTE: NC Cooperative Extension will be taking over the Blackberry and Raspberry Information Portal in early 2013. The site will have essentially the same material, but a new look. Links will be provided from the old site to the new site.

***This information (originally written by me) also appears in the latest SRSFC newsletter******

Pack 'N Cool mobile chilling unit

Dr. Penny Perkins-Veazie and her team, at the NC State University Plants for Human Health Institute have developed a mobile chilling unit, called a Pack 'N Cool,  for farmers in need of a "smaller" trailer to haul produce to markets.

There is a full news release at the site below, with links to a step-by-step instruction on how to build the unit and a detailed budget. For more information click here: http://plantsforhumanhealth.ncsu.edu/2012/08/17/“pack-‘n-cool”-provides-farmers-with-mobile-refrigeration-solution/

This same unit was used as part of an Extension Agent Training earlier this year. http://teamrubus.blogspot.com/2012/07/post-harvest-agent-training.html

Meet 'Von', a new thornless blackberry

'Von' thornless erect blackberry.

‘Von’ is the first erect thornless floricane-fruiting blackberry to be released from the NC State University caneberry breeding program.  ‘Von’ is named after Harvey Von Underwood, who was a Researcher at NC State University. Mr. Underwood worked at NC State University muscadine and bramble breeding program in the 1950’s-70’s and was responsible for saving valuable germplasm from those programs.

'Von' was selected by Jim Ballington in 1998 as tested as NC 430. We have been evaluating 'Von'   at the Mountain Research Station in Laurel Springs, the Moutain Hort Crops Research and Extension Center in Mills River and at the Piedmont Research Station in Salisbury, NC. Dr. Penny Perkins-Veazie conducted extensive post harvest evaluation of 'Von' since her arrival at NCSU in 2009.

Here are some key attributes of 'Von':

• In a replicated trial at the Piedmont Research Station in Salisbury NC, total yield of ‘Von’ was 12,017 g/plant (24063 lbs/acre).

• In that same trial, marketable yield of ‘Von’ was 10,704 g/plant (21,434 lbs/acre). 

• Fruit of ‘Von’ is medium size  (6.6 g) has smaller drupelet and seed size compared to other cultivars.

• ‘Von’ produces fruit in the late season, with average date of harvest commencing in the third week of June, peaking in the second week of July and ending the first week of August. 

• ‘Von’ has a marketable post harvest score of 90.6, which is as good or better than the leading commercial cultivars.

• Soluble sugars content of ‘Von’ was 9.4% and pH was 3.57, traits that characterize ‘Von’ as sweet with low acid. 

I will be posting a list of nurseries that will be propagating 'Von' later this year. 

For list of nurseries propagating Von go to
http://teamrubus.blogspot.com/2013/09/nursery-list-for-von-blackberry.html

Can raspberries be picked pink for fresh markets?

By Penelope Perkins-Veazie, Plants for Human Health Institute, North Carolina State University and Gina Fernandez, Department of Horticultural Science NC State University

Raspberries are the most perishable of the temperate fruit crops. If you set them on your kitchen counter, you can watch the mold grow within 24 hours. This fruit’s delicate nature is due to its fragile structure, where drupelets are connected together by only a few trichomes (fruit hairs), no cuticle is present, and gray mold (Botrytis cinerea) can set up spores during bloom and produce fuzzy gray fruit as the berries are ripening.

While raspberry fruit mostly produce ethylene from the fruit calyx (the part of the fruit that remains on the plant), there is a small amount of ethylene, the fruit ripening hormone, present in many varieties. This actually can pose an advantage for fruit growers producing raspberries in the warmer parts of the season. Fruit at the pink or even pink-yellow stage will often detach from the calyx with minimal tugging.

We initiated a small test in 2010 to investigate the ability of raspberries to attain full ripeness if harvested unripe. These fruit were harvested in August and September from plants grown in high tunnels at the Upper Mountain Research Station, Laurel Springs, NC. Temperatures within the tunnels were above 85°F for approximately four hours per day. Unripe and ripe raspberries were picked at weekly intervals for the tests, over a three-week period, and one to two clamshells per cultivar and ripeness were used for the study. 

Raspberries were picked into halfpint clamshells and transported at 5°C in refrigerated ice chests (Kooltron) to Kannapolis, and held at 39 °F for six days. Subsamples were removed at day 0 to check firmness, color, sugars, and acidity. Subjective ratings were taken after storage by checking each berry for softness, leak, and mold. The overall color of the fruit within the clamshell was determined subjectively as 0 (light red) to 3 (dark purple red). Percent saleable fruit was determined by using the relationship of color to percent (where rating of 0 was 100% saleable to 3 was 0% saleable).

Surprisingly, even fruit picked considerably unripe (yellow-pink) achieved full color, soluble solids content, acidity, and flavor (tasted at random) after six days storage (Table 1). The biggest disadvantage of picking unripe berries was a depression in berry size of 4% to 20%, depending on variety and relative ripeness at harvest. What was clear from ratings was that fruit picked pink was much firmer and less leaky than berries picked at the normal commercial fresh market ripe stage (Table 2). The amount of moldy berries was slight (less than 10%), due to a rigorous fungicide spray program and the protective effect of the tunnels from moisture and wind.

We hoped that berries varieties known to turn dark red after storage, such as Joan J, would be less fully red if picked pink prior to storage. In fact, we found that color could not be slowed enough, with fruit reaching full color as soon as 2 days at 39° F after harvest. Figure 1 illustrates the change in color of ‘Culivar’ in ripe and unripe berries at 0, 5 and 10 days after harvest.

Flavonoids are compounds are compounds  that are associated with health benefits, and higher levels in fruit are good. Flavonoids in raspberry include the anthocyanins that give raspberries much of their red color, along with other colorless phenolic compounds. In raspberries picked before full ripeness, flavonoid content was decreased by 5-15% after storage. The slight loss in flavonoids in the less ripe fruit was madeup in the better appearance and firmness of the raspberries.

Harvesting raspberries at the pink stage is possible. We did not observe significant problems with composition and flavor, and early picking improves the number of marketable fruit. However, harvesting less ripe fruit is likely dependent on air temperature (detaching raspberries is difficult in cool weather), and will require more attention and training of pickers during harvest than pulling off fully ripe berries. Although we did not determine optimal temperatures for picking unripe berries in this study, the ability of raspberries to fully color up and soften may depend greatly on having a production environment where temperatures are at 75° F for at least four hours.

Table 1.  Comparison of raspberry fruit harvested unripe (pink) or ripe (red)
before and after storage at 4C, averaged for Joan J, Nantahala, Caroline
Variant	Days	Unripe	Ripe	Mean
Total phenolics	0	2858	2866	2862
(mg/kg gallic acid equivalents)	6	3090	3144	3117*
Total anthocyanin	0	508	530	519
(mg/kg cyan-3-glucoside equivalents)	6	510	589	550*
FRAP (Ferric reducing antioxidant potential)	0	28.6	26.8	27.7
(umol/g trolox equivalents)	6	28.5	28.8	28.6
Soluble solids content (%)	0	11.2	10.9	11.1
	6	11.9	11.7	11.8
Titratable acidity (%)	0	1.23	1.26	1.24
	6	1.05*	1.19*	1.12*
Means separated within column and days 0,6 using student's t-test, P<5%.

Table 2.  Comparison of raspberries picked unripe (pink) or ripe (red) after storage at 4C for 6 days
	%Leaky berries		%Soft		%Saleable	color
Variety	Unripe	Ripe	Unripe	Ripe	Unripe	Ripe
Autumn Britten	1a	42b	48ab	93a	43b	7b
Caroline	8a	19a	61a	86ab	47b	33ab
Nantahala	2a	37b	38b	75b	67a	47a
Mean	3a	33*	49	82*	52	29*
Means separated within column among cultivars, by letter (P<5%) using REGWQ.

The original version of this article (including photos) appears in Autumn 2011 issue of "The Bramble."  To access this article, you must be a member of the North American Raspberry and Blackberry Association. To become a member to: http://www.raspberryblackberry.com/index.cfm and click on Membership in the left purple panel. 

Caneberry Workshop

The Caneberry Workshop was a great success. We had over 60 participants, most were from North Carolina, but some even came from Illinois, Virginia and Kentucky! One of the goals of the workshop was to generate interest in growing caneberries in this part of the state. I think we succeeded in generating interest, I am hopeful that we will see some production in this area in the future.

The workshop featured work being done at the station by Drs. Hannah Burrack, Penny Perkins-Veazie and myself. (NB - this may have been the first workshop lead by all female NCSU faculty in history!) Dr. Burrack focused on her Spotted Wing Drosophila work, Dr. Veazie discussed pre and post harvest handling of fruit and I talked about the replicated trials of blackberries and raspberries in and out of tunnels.

I gave the participants a tour of the replicated breeding trials. The caneberry breeding program has several locations where we test our materials. One of the locations is here at the Upper Mountain Reserach Station in Laurel Springs. This is our highest sight, at about 2500-3000' elevation and is in USDA hardiness zone 6. The average high temperatures in summers are in the low 80's and nights are cool as well....compared to the rest of the state. Raspberries love it here!

At this location we have one of our mirror 'variety' trials. We have a mix of varieties and selections from our breeding program, USDA and other Univ. breeding programs as well as recently named varieties. Each of the varieties was growing both under high tunnels and outside of tunnels. This allows us to compare overall growth, ripening season and fruit quality among lots of other attributes. Primocane fruiting raspberries were in the early part of their season, while floricane fruiting types had finished a couple of weeks ago. Floricane fruiting blackberries were still producing fruit and primocane fruiting types were flowering and had lots of green fruit. We will post the data on the NC Market Ready Portal at the end of the season here: http://ncsu.edu/enterprises/blackberries-raspberries/production/latest-research/
(There is data from other locations at this site that you may want to check out as well).

Dr. Penny Perkins-Veazie discussed pre and post harvest handling of raspberry and blackberry fruit. Participants comments included, "I never knew raspberries came in so many different colors of red". They also learned that most customers don't like dark red berries. She also discussed how picking pink berries will last longer on the shelf.  She recently wrote an article about this. I will post a link on a later blog post.

Dr. Hannah Burrack discussed her work with spotted wing drosophila (SWD). This location is what she calls "Ground Zero" for SWD. Participants got to see SWD in all of its stages and learn more about how it impacts fruit production. She has a blog of her own where she regularly updates her findings. http://ncsmallfruitsipm.blogspot.com/p/spotted-wing-drosophila.html

A BIG thanks to all of the folks at the Upper Mountain Research Station that helped get the fields looking tip top and setting up the field and inside venue. I sincerely appreciate all you do for the caneberry programs. Sponsors included the College of Agriculture and Life Sciences, the North Carolina Agricultural Research Service and the North Carolina Cooperative Extension Service at N.C. State University; the N.C. Department of Agriculture and Consumer Services; and the N.C. Tobacco Trust Fund Commission.

Blackberry and Raspberry Post Harvest Evaluation

Evaluation of blackberry post harvest traits

We have an amazing team of scientists at NC State University working on blackberries and raspberries (Team Rubus). One of the newer members of our team is Dr. Penny Perkins-Veazie. Dr. Perkins-Veazie, worked for many years at USDA-ARS as a post harvest physiologist. She is  now located at the Plants for Human Health Institute at the NC Research Campus in Kannapolis. One of the projects we have is the evaluation of raspberry and blackberry fruit post harvest traits. She is also working to determine which varieties contain antioxidant compounds in Rubus fruit.

In the picture above, Dr. Perkins-Veazie shows a graduate student how to evaluate the post harvest traits of blackberries.

There is You Tube a video link to this protocol at:

http://plantsforhumanhealth.ncsu.edu/2011/03/31/rating-blackberries-raspberries-for-postharvest-quality/

Award Winning Student!

Christine Bradish, a MS candidate just returned from the Berry Health Symposium #berryhealth. She won 1st place in the poster competition.  Christine is working with Drs. Penny Perkins, Wei Jei and myself and is in the final stages of her MS degree at NC State University.


Christine looked for flavonoids in red raspberry that are known to be good for you.  She used metabolite-profiling to qualify, quantify, and compare major flavonoid compounds in primocane-fruiting red raspberry cultivars grown at three locations with varying elevation and average temperatures in North Carolina. 


She found:
 •There was significant qualitative and quantitative differences in the metabolite profiles, due to variation in cultivar, location, and environmental factors. (=not all raspberries are the same in terms of health benefits)

•Plants exposed to longer durations of heat stress (over 85°F) had higher total phenolics measurements and antioxidant capacity due to greater production of flavonoid secondary metabolites. (=stress may increase the good compounds in berries)

Implications: 

•Utilization of metabolite profiles, such as the ones in this study, could help breeding programs identify key metabolites contributing to antioxidant properties, and define the genotype-by-environment interactions on them. 

•This technology may be useful for the development of nutritionally enhanced varieties, and further tailoring for functional foods.

The link to the proceedings is below. Her abstract is on page 61.
http://www.berryhealth.org/Information/2011_preproceedings_sm.pdf