Arkansas Blackberry Field Day brings research together from across the Southeast
June 17, 2026
By John Lovett
University of Arkansas Division of Agriculture
Fast Facts
- Results of studies presented on insect control, production techniques, cultivar field trials
- Arkansas study shows persistence of Spotted Wing Drosophila
- Gov. Sanders proclaims June as Arkansas Blackberry Month
(1,267 words)
Download PHOTOS from the Blackberry Field Day
CLARKSVILLE, Ark. — The latest in blackberry research, including production techniques, insect control, cultivar field trials and marketing, took center stage at the 10th annual Blackberry Field Day at the Arkansas Fruit Research Station.
Over 100 people gathered for the University of Arkansas Division of Agriculture event, including Arkansas blackberry growers and researchers from land-grant universities in Florida, Georgia, North Carolina and South Carolina. The field day is co-sponsored by the Arkansas Blackberry Growers Association.
“Our program has been ongoing since 1964, and we are the nation’s, maybe the world’s, largest public-sector blackberry breeding program,” said Margaret Worthington, an associate professor in the department of horticulture and director of the Fruit Breeding Program for the Arkansas Agricultural Experiment Station, the research arm of the Division of Agriculture.
Blackberries are the leading crop of the Fruit Breeding Program, with 43 varieties developed for early, mid and late season harvesting, each with its own distinct flavor profiles and post-harvest qualities. Arkansas-developed varieties like Sweet-Ark™ Caddo are grown across the nation and bring in about $1.5 million in royalties each year to support the breeding program and the Fruit Research Station. Researchers with theprogram also developed the world’s first primocane-fruiting blackberries that flower and fruit on first-year canes.
“We’re very focused on the fresh market here and make about 65 crosses a year, planting about 8,000 blackberry seedlings in the ground,” Worthington said. “From there, we pick about 100 a year to go into trial, and we can pick about 10 a year that make it to replicated trials that we think are worth testing for yield.”
At the field day, which took place on June 9, Arkansas Secretary of Agriculture Wes Ward presented a proclamation from Gov. Sarah Sanders recognizing June as Arkansas Blackberry Month. The proclamation noted the Fruit Breeding Program’s developments of primocane, thornless and late-season cultivars and how blackberries provide supplemental income for many rural families.
Meeting consumer demand
Melissa Muñoz, a small fruit horticulturist for Clemson University, said consumer demand for blackberries has increased over the past 10 years, and growers in South Carolina are looking to plant varieties with lower chill-hour requirements to improve production.
Blackberry plants require a certain number of winter chilling hours — temperatures from 32 to 45 degrees Fahrenheit — to support growth and fruiting.
“The farms that are going to do blackberries are putting more blackberries in their fields, with their main focus on U-pick and direct marketing,” she said. “The whole idea here for the growers has been to increase the harvest windows, especially those U-picks. That’s what’s going to keep their operations running and money flowing.”
Dealing with the heat
Zilfina Rubio, assistant professor and small fruit extension specialist in the department of horticulture for the University of Georgia, provided an overview of a study on the chill-hour requirements of 12 blackberry varieties grown in Georgia. In general, she said, the maximum chill hours for growers in Georgia would be in the 400 to 500-hour range.
The study also looked at percentages of red-drupelet reversion, which refers to parts of a ripe blackberry turning red again due to heat stress.
Other visiting researchers who gave presentations included Muhammed Shahid, an assistant professor of horticulture specializing in stress physiology of fruit crops at the University of Florida’s Institute of Food and Agricultural Sciences, and Lorena Lopez, an assistant extension professor for the department of entomology and plant pathology at North Carolina State University.
Shahid said, despite the heat, north Florida has become a hub of the state’s blackberry production by adopting practices used by tomato and cigar tobacco farmers, such as shade screens. His research showed a screen that blocks 40% of the sun was optimal to retain photosynthesis.
Growers in Florida are also experimenting with growing blackberries in containers that can be stored in walk-in coolers to meet chill-hour requirements and then moving them to hoop houses to start producing berries earlier in the season.
Pest predators and insecticide
Lopez and Aaron Cato, an associate professor and extension specialist of horticulture and integrated pest management for the Division of Agriculture, collaborated on a project promoting the value of thrips and mite monitoring in small fruits. Their work is helping farmers understand which thrips species are feeding on crops like blackberries, and the benefits of predatory mites like the native Neoseiulus fallacis that feeds on both spider mites and broad mites.
“Typically, we recommend spraying as drupelets on fruit begin to turn black, and about seven to 10 days prior to the first picking,” Cato said.
For Spotted Wing Drosophila, an invasive fruit fly that is now a common insect problem in Arkansas blackberries, Cato said growers tend to start spraying insecticides too late.
In an insecticide field trial last year on blackberries for the fruit fly, Cato said one to two larvae were found on every single fruit in the third week of picking, when they started their insecticide spray schedule about one to two weeks late. It’s a common mistake growers make, he said.
During the study, the number of larvae decreased slightly over time when spraying weekly during the picking season. However, the lowest they could get the larvae numbers down while spraying after harvest started was one fruit fly larva per blackberry.
“You need insecticide to help with spotted wing, but they will absolutely not do that much for you if you get to them late,” he said.
To help control the fruit fly, Cato recommends an integrated management approach with pruning to open the blackberry plant canopy since the fruit flies do not like sunlight or high heat. Additionally, Cato recommends growers get rid of any non-marketable fruit or culls, harvest every one to two days to lower the risk of infestation, move picked fruit immediately to cold storage and rotate insecticides to limit resistance.
Robot pickers and growing in containers
Updates were also provided to field day goers on innovative projects to develop a robot to pick blackberries and the “long-cane method” of growing blackberries in soilless substrate containers.
Renee Threlfall, an associate professor and research scientist in enology and viticulture in the department of food science for the Division of Agriculture and the Dale Bumpers College of Agricultural, Food and Life Sciences, provided an overview of a blackberry-picking robot project she has worked on with Anthony Gunderman, an assistant professor of mechanical engineering in the University of Arkansas College of Engineering.
Ryan Dickson, an associate professor and greenhouse and container crops specialist in the department of horticulture for the Division of Agriculture and Bumpers College, said he and his team are still looking into theprofitability of the long-cane system. So far, however, studies have shown that the plants are high-yielding and produce large, flavorful fruit.
With the long-cane system, the blackberry plants are first grown outdoors in containers filled with a soilless substrate and trained to form long canes for high-density production in high tunnels or greenhouses after being stored in a walk-in cooler to satisfy the dormancy and chill-hour requirements. Potential benefits of the long-cane blackberry system are increased yields, consistent fruit quality and the ability to time harvests for more lucrative out-of-season production.
The Arkansas Agricultural Experiment Station and the respective research centers at Clemson University, the University of Georgia, the University of Florida, and North Carolina State University are part of a system of1862 and 1890 land-grant universities in the southern U.S., where scientists collaborate to conduct research and outreach focused on preserving the region’s natural resources and enhancing food production for a growing global population.
A dozen horticulture department heads from across the nation also attended the field day with Mary Savin, head of the department of horticulture for the Division of Agriculture and Bumpers College, as part of a two-day meeting to discuss collaborations.
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To learn more about ag and food research in Arkansas, visit aaes.uada.edu. Follow the Arkansas Agricultural Experiment Station on LinkedIn and sign up for our monthly newsletter, the Arkansas Agricultural Research Report. To learn more about the Division of Agriculture, visit uada.edu. To learn about extension programs in Arkansas, contact your local Cooperative Extension Service agent or visit uaex.uada.edu.
About the Division of Agriculture
The University of Arkansas Division of Agriculture’s mission is to strengthen agriculture, communities, and families by connecting trusted research to the adoption of best practices. Through the Agricultural Experiment Station and the Cooperative Extension Service, the Division of Agriculture conducts research and extension work within the nation’s historic land grant education system.
The Division of Agriculture is one of 22 entities within the University of Arkansas System. It has offices in all 75 counties in Arkansas and faculty on three system campuses.
Pursuant to 7 CFR § 15.3, the University of Arkansas Division of Agriculture offers all its Extension and Research programs and services (including employment) without regard to race, color, sex, national origin, religion, age, disability, marital or veteran status, genetic information, sexual preference, pregnancy or any other legally protected status, and is an equal opportunity institution.
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Media Contact:
John Lovett
U of A Division of Agriculture
Arkansas Agricultural Experiment Station
(479) 763-5929
jlovett@uada.edu