Pick up know-how for tackling diseases, pests and weeds.
Farm bill, farm marketing, agribusiness webinars, & farm policy.
Find tactics for healthy livestock and sound forages.
Scheduling and methods of irrigation.
Explore our Extension locations around the state.
Commercial row crop production in Arkansas.
Agriculture weed management resources.
Use virtual and real tools to improve critical calculations for farms and ranches.
Learn to ID forages and more.
Explore our research locations around the state.
Get the latest research results from our county agents.
Our programs include aquaculture, diagnostics, and energy conservation.
Keep our food, fiber and fuel supplies safe from disaster.
Private, Commercial & Non-commercial training and education.
Specialty crops including turfgrass, vegetables, fruits, and ornamentals.
Find educational resources and get youth engaged in agriculture.
Gaining garden smarts and sharing skills.
Creating beauty in and around the home.
Maintenance calendar, and best practices.
Coaxing the best produce from asparagus to zucchini.
What’s wrong with my plants? The clinic can help.
Featured trees, vines, shrubs and flowers.
Ask our experts plant, animal, or insect questions.
Enjoying the sweet fruits of your labor.
Herbs, native plants, & reference desk QA.
Growing together from youth to maturity.
Crapemyrtles, hydrangeas, hort glossary, and weed ID databases.
Get beekeeping, honey production, and class information.
Grow a pollinator-friendly garden.
Schedule these timely events on your gardening calendar.
Equipping individuals to lead organizations, communities, and regions.
Guiding communities and regions toward vibrant and sustainable futures.
Guiding entrepreneurs from concept to profit.
Position your business to compete for government contracts.
Find trends, opportunities and impacts.
Providing unbiased information to enable educated votes on critical issues.
Increase your knowledge of public issues & get involved.
Research-based connection to government and policy issues.
Support Arkansas local food initiatives.
Read about our efforts.
Preparing for and recovering from disasters.
Licensing for forestry and wildlife professionals.
Preserving water quality and quantity.
Cleaner air for healthier living.
Firewood & bioenergy resources.
Managing a complex forest ecosystem.
Read about nature across Arkansas and the U.S.
Learn to manage wildlife on your land.
Soil quality and its use here in Arkansas.
Learn to ID unwanted plant and animal visitors.
Timely updates from our specialists.
Eating right and staying healthy.
Ensuring safe meals.
Take charge of your well-being.
Cooking with Arkansas foods.
Making the most of your money.
Making sound choices for families and ourselves.
Nurturing our future.
Get tips for food, fitness, finance, and more!
Understanding aging and its effects.
Giving back to the community.
Managing safely when disaster strikes.
Listen to our latest episode!
Amanda McWhirtExtension Fruit & Nut Specialist Phone: 501-671-2229Email: firstname.lastname@example.org
Jackie LeeExt Spec-Horticulture IPM Phone: 501-671-2191Email: email@example.com
by Amanda McWhirt - June 22, 2017
Here is a guide to help you identify what is going on with misshapen, off-color or
otherwise odd looking blackberries.
But before we can talk about what causes blackberry fruit to develop odd shapes and
colors, we need to discuss how blackberries form in the first place.
The word “berry” in the name blackberry is misleading as they are in fact not true
berries in a botanical sense. True berries are formed from only one ovary in one flower.
Blackberry flowers can have over 100 ovaries! (Oddly one example of a true berry is bananas).
Instead blackberries are what is called an aggregate fruit, and their fruit is composed
of 75-85 small druplets (see diagram below). Most blackberry disorders affect the
druplets in some way that the overall result in an unappealing or unedible fruit.
There are several different types of disorders that can affect blackberry fruit. Abiotic
disorders are caused by non-living parts of the environment like temperature or weather.
Living organisms like insects and disease can also cause berries to become misshapen
I will discuss a few examples of each of these types of blackberry disorders.
Poor Pollination/ Poor Druplet Formation
Poor druplet formation can arise due to poor pollination of flowers. Pollen is produced
in the stamens of the flower and must be moved to the pistils to fertilize the ovules,
which will result in the druplet. If the pistil is not fertilized no druplet will
form. Blackberry flowers have 100-125 pistils of which 75-85 must be fertilized to
get a good sized and shaped berry.
While blackberry flowers are self-fertile, bees are important for ensuring good pollination.
Berries that have poor druplet formation are more common following cool, cloudy or
wet conditions during flowering, because bees are less active in these conditions.
Viruses can be a major issue for blackberry production in the Southeast. A buildup
of viruses in the crop can ultimately result in a slow decline to crop health, yields
and fruit quality. The best way to avoid these issues is to start with healthy and
clean plant material at crop establishment.
Other names “Red Cell Reversion” “Red Druplet Disorder” or “Red Cell”
Have you ever picked some dark-black ripe blackberries on a hot day, put them in your
refrigerator and returned later only to see some of the druplets had turned back to
red? This reversion of druplet color after harvest or cooling is associated with rapid
temperature changes in the environment or in the berry.
This phenomenon is only recently being better understood, and the exact chemical reaction
is still not fully understood.
Prevention is key to managing this disorder. Ways to prevent or reduce red cell regression
It is important to realize the fruit is still edible and no change in sugar content
has been identified between normal and reverted druplets. These berries may best be
marketed for jams or pies.
Grocery stores have a low tolerance for red cell regression in loads and may reject
loads where greater than 15% of the berries exhibit red cell regression. Renee Threlfall
of the University of Arkansas- Department of Food Science has done work that has found
consumers perceive berries with red cell regression to be “under-ripe” berries, despite
that they are in-fact ripe.
Consumer education may be important to managing this issue particularly with certain
varieties. Some work has indicated that ‘Natchez’ may be more prone to this disorder
than new releases like ‘Osage’. More work continues to be done on this topic and I
will update this post as results are released.
Max Edgley out of Australia has conducted much of the recent work on this topic. Some
of his results can be found here.
White druplet is associated with a drop in humidity and an increase in temperature.
As this happens there is less moisture in the air to deflect solar radiation from
directly contacting the berries. This increased solar radiation is blamed on individual
or groups of druplets turning first white and then later brown in color.
This disorder is often a problem early on in the season and may lessen as the season
progresses. ‘Apache’ is a variety that is more prone to this disorder.
Orienting the trellis to shade the fruit for most of the day is a method to prevent
this disorder on susceptible varieties.
Sunburn of fruit is commonly seen when daytime temperatures exceed 90 degrees or more. At
these temperatures fruit in direct sunlight may reach temperatures that exceed the
air temperature by several degrees (see here for more information). When this occurs the fruit is essentially boiled by the sun.
Symptoms include druplets that look “blanched” or “cooked”.
Generally symptoms are present on only the side of the fruit exposed to the sun and
the shaded side of the fruit will not have any damage.
This disorder is often associated with white drupe and both symptoms may be present
at the same time.
Prevention methods include closely picking berries every few days, encouraging good
plant health so that there is sufficient leaf cover to protect berries from the sun
and orienting the trellis to shade the fruit for most of the day.
Dr. John Clark reports seeing double berry occur on primocane fruiting varieties when
there are high temperatures just prior to or during flowering. This is important to
remember for us here in Arkansas as our primocane fruiters generally set flowers in
the heat of summer.
Occurrence is variety dependent with more double berry occurring on 'Prime-Ark® Freedom'
and 'Prime-Ark® 45' than on 'Prime-Ark® Traveler'.
Spotted wing drosophila is a relatively new pest to blackberries in the SE. The first
populations of these flies were found in Arkansas in 2012. The female flies lay eggs
in ripening fruit which then develop into larvae. These flies are not native to the
United States and differ from their fruit fly cousins in that they have a large serrated
ovipositor that makes it easy for them to lay eggs in undamaged fruit that is still
on the cane.
I will attach a rough video here of a SWD larvae in a blackberry fruit. This was identified
because of a soft and broken druplet that was leaking that you can see on the left
side of the berry. After leaving the berry in a cup for several minutes at room temperature
the larvae emerged.
Dr. Jackie Lee, University of Arkansas IPM Specialist, has said this is the time (Late
June/ Early July) for SWD populations to be peaking here in Arkansas. Jackie advises
that one of the best cultural management practices to lessen SWD infestations is to
pick berries regularly to avoid leaving fruit open to infestation in the field. Also
getting berries into the cooler soon after picking can halt larval development. These practices should be paired with a management program utilizing conventional
or organic pesticides sprayed every 7-10 days. Consult the MP-144 for a list of registered products.
Consumers and grocery stores have a zero tolerance for these larvae in fruit.
***Suspected*** These pictures are of berries suspected to have red berry mite, it has not been confirmed
A distinct line between ripe black druplets and unripe red druplets that fail to ripen
is a sign of the redberry mite (Acalitus essigi). As this mite feeds on the fruit
it injects a toxin that results in the sharp contrast. This occurrence tends to be
more common on late bearing blackberry varieties.
It is controlled by lime sulfur sprays during dormancy or horticultural oils in season.
Some varieties are slow to ripen and this should not be confused with mite damage.
Generally this is not a major pest in AR.
Stinkbugs feed on the fruit receptacle (the white part at the center of the fruit)
and in doing so damage druplets as they insert their mouthparts. Stinkbugs may feed
on green, red or black fruit.
Generally their feeding results in only localized damage to one or two druplets. A
secondary type of damage can occur if the stink bug injects its "stink" into the fruit
while it is feeding. This may result in a blackberry fruit that can “taste like a
stink bug smells”.
Dr. Jackie Lee recommends treating for stinkbug when you see them in the nymphal stages
as they are easier to control at that stage of development.
Consult the MP-144 for a list of registered products for stink bug management.
Keep in mind the PHI (Preharvest Interval) for each product particularly during peak
Brown crumbly, shrunken druplets are a sign of anthracnose. Anthracnose also causes
silvery lesions on the floricanes and if both the berry symptoms and cane symptoms
are present that is a good sign it is in fact anthracnose.
Prevention of anthracnose is key and is generally done with a lime sulfur or sulfuric
sprays in winter during dormancy.
Options for control of Anthracnose during harvest include Abound and Switch are options
with 0 PHI.
Consult your Arkansas Plant Disease Control Products Guide MP154 for more information on rates.
***Suspected*** This is another suspected issue in these pictures, not confirmed
These symptoms may be related to anthracnose, but the symptoms on this berry were
hard druplets instead of more crumbly druplets typically seen on anthracnose infected
The cause of Dry cell, or Dry berry syndrome is unknown but it has been associated
with the following:
The occurrence of this disorder is more common in years with heavy late spring rains.
This year we have had these conditions and I have seen or heard of these symptoms
from several locations in Arkansas and the surrounding area. Treatment is usually
targeted at the diseases associated with the occurrence of these symptoms as the cause
I will end this post with a non-berry related blackberry disorder that pops up only
occasionally and doesn’t cause any real damage- but is striking when it does occur.
It is called Fasciation.
Fasciation is a phenomena that is an abnormal growth of the growing point of the plant
that results in the plant part affected taking on an abnormal and generally elongated
shape. This disorder can affect many different types of plants. Cockscomb is a good
example of the odd elongated wavy shapes that might occur and is also an example of
fasciation that is inherited.
In this case fasciation on a blackberry primocane results in a flattened almost 1.5’’
A blackberry plant may produce this trait on only one cane in a single year and then
The cause of this type of abnormal development has been attributed to environmental
factors, herbicide, disease, insect feeding, virus and more. Generally it is isolated
and is not contagious or prone to spread.
Fasciated canes may be removed or if curiosity strikes you they can be left to see
if they develop odd shaped flowers or fruit in their fruiting year.
The example below if from a farm in NE Arkansas who reports finding at least one of
these canes per year.