Projects
See what we’ve been working on, what we have learned so far, and what we have planned for the future.
Tea Varietal Assessment
Our first tea project was simple: acquire as many distinct varieties as we could find available in the southeastern US, plant them, and see how they performed here in Florida. This work was initially funded by a 2015 FDACS Specialty Crop block grant (FDACS #022918). The project goals were to collect and test some of the most readily available tea varieties in the southeastern US for performance under Florida growing conditions, to document any disease problems that occurred, and to determine which varieties may have better heat tolerance and disease resistance than others. As of the end of the 2-year grant period, ‘Big leaf’/ ‘Large leaf,’ ‘Fairhope,’ and ‘China’ had the best survival; ‘Fairhope,’ ‘Georgia,’ and ‘Big leaf’/ ‘Large leaf’ had the highest yields; and ‘Big leaf’/ ‘Large leaf’ and ‘Fairhope’ showed the greatest field resistance to anthracnose. Data collection on these plants is continuing, and additional varieties have been added, using donated and program funds to cover the costs of plot maintenance.
Publications:
Orrock, J. M., B. Rathinasabapathi, and B. Spakes Richter. 2019. Anthracnose in U.S. Tea: Pathogen characterization and susceptibility among six tea accessions. Plant Disease. 104:1055–1059. DOI:10.1094/PDIS-07-19-1518-RE
Orrock, J. M., Richter, B. S., and Rathinasabapathi, B. 2021. Performance of Seven Tea Accessions in North-central Florida: Correlations between potential yield and growth parameters over 2 years. HortTechnology. 31:1–7. DOI:10.21273/HORTTECH04908-21
Conference Presentations & Posters:
Orrock, J. M., B. Spakes Richter, and B. Rathinasabapathi. 2017. Tea as a novel crop for Florida: field establishment of eight accessions. FHSH Annual Meeting, Jun4-6, Tampa, FL. Proc. Fla. State Hort. Soc. 130:35–36.
Growing Systems for Tea Production in Florida
Through our varietal trial we identified a few varieties that grew well in north-central Florida, but along the way, we realized that weed competition was going to be a major challenge in getting young plants established. It takes several years before the tea plants grow large enough to begin shading out the surrounding weeds, and we wanted to determine whether weed barrier fabric (which can be expensive and degrades in sunlight, requiring replacement every few years) was really the best approach. This project was funded by a 2018 USDA Southern SARE grant (SARE #LS18-297) to examine companion cover crops for tea production, including impacts on tea growth and yield, weed suppression, soil nutrient cycling, and disease incidence. We established tea plots in cooperation with two local growers in Alachua and Marion counties, using three tea varieties (‘Large leaf,’ and ‘Fairhope,’ from our earlier trial, and a newer addition, ‘Red leaf’), three ground cover treatments (weed barrier fabric, perennial peanut, and an annual crimson clover rotation), and two shade trees (initially, moringa and persimmon). While weed barrier fabric provided superior suppression of weed competition, and plants in this treatment had higher early yields (3 years after planting), weed barrier fabric did not improve plant survival and had a negative impact on soil nutrients and nutrient cycling microbial populations.
Part of this project was to establish potential companion shade trees, as lowland tea production in other parts of the world often utilizes shade trees to protect tea leaves from high sun intensity, as we experience here in Florida. At our test sites, Moringa trees did not rebound sufficiently from frost events to provide shading during the early summer, when the plants most need it, and was replaced by everbearing mulberry, which grew well but required frequent pruning to keep low-hanging branches from interfering with tea maintenance and harvest. Persimmon had the best survival and value added (salable fruit), and good compatibility with the tea-growing system. We left unplanted tea rows in this system for future plantings to test the impacts of shade on tea plant establishment. Now that the persimmon trees are large enough to provide significant shade, plans are underway to embark on the next phase of this work.
Publications:
McAmis, S., H. Bae, A. Ogram, B. Rathinasabapathi, and B.S. Richter. 2024. Living mulches present tradeoffs between soil nutrient cycling and competition during establishment of tea in an organic production system. Appl. Soil Ecol. 198: 105350. DOI: 10.1016/j.apsoil.2024.105350.
Conference Presentations & Posters:
McAmis, S.K., B. Rathinasabapathi, and B.S. Richter. 2021. Ground cover growing systems for tea production in Florida. FSHS Annual Meeting, Jun 4-6, Tampa, FL. Proc. Fla. State Hort. Soc. 134:42.
Pathogens on and Around Florida Tea
In our varietal trial we found that one disease was consistently prevalent: anthracnose, caused by the fungus, Colletotrichum camelliae. We also observed algal leaf spot, especially on older leaves, and a few other leaf spots that were less common. This is consistent with tea production around the world, where multiple species of Colletotrichum are known to cause losses in tea. We conducted a survey of Colletotrichum species on and around tea plants, as well as around ornamental camellias and blueberries (both considered likely to be planted near tea, either during transplant production or field production), and we found that there are actually two species of Colletotrichum on tea in Florida, and that several unrelated weed species can harbor Colletotrichum fungi that are capable of infecting tea. This work was funded in part by the USDA-SARE grant above (#LS18-297), and in part by the McIntire-Stennis Cooperative Forestry capacity funding program (FLA-PLP-005884).
Publications:
Soltez, K., D.E. Soltis, and B. Spakes-Richter. 2025. Surrounded: Inoculum sources of Colletotrichum gloeosporioides complex pathogens around Florida Ericales crops: tea, camellia, and blueberry. Plant Disease 110(3):934-943. DOI:10.1094/PDIS-08-24-1643-RE.
Orrock, J., B. Rathinasabapathi, B. Spakes-Richter. 2020. Anthracnose in US tea: pathogen characterization and susceptibility among six tea accessions. Plant Disease 104: 1055-1059. DOI:10.1094/PDIS-07-19-1518-RE.
Conference Presentations & Posters:
Soltez, K. and B. Spakes-Richter. 2023. Survey of Colletotrichum spp. found on weeds around Camellia sinensis. Poster P-499. American Phytopathological Society Plant Health 2023, Aug 12-16, Denver, CO.
Soltez, K. and B. Spakes-Richter. 2023. Tracking Colletotrichum camelliae in the fruits and seeds of Camellia sinensis in Florida. American Phytopathological Society Southern Division meeting, Feb 13-16, Durham, NC. DOI:10.1094/PHYTO-113-9-S2.30
Orrock, J., B. Rathinasabapathi, B. Spakes-Richter. 2019. Diversity of Colletotrichum species on tea (Camellia sinensis) from three counties in Florida. Poster 608-P2. American Phytopathological Society Plant Health 2019, Aug 3-7, Cleveland, OH.
Orrock, J., B. Rathinasabapathi, B. Spakes-Richter. 2018. Anthracnose disease ratings on tea (Camellia sinensis) during the growing season in Florida. Poster 1003-P. International Congress of Plant Pathology (ICPP), Jul 29-Aug 3, Boston, MA.
Orrock, J., K. Kemfert, K. Sandsted, R. Healy, B. Spakes-Richter. 2017. An assessment of putative foliar pathogens on different accessions of tea grown in Florida. Poster 432-P. American Phytopathological Society Annual meeting, August 5-9, San Antionio, TX.
Florida Tea’s Insect Friends and Foes
One of the great things about growing tea in Florida is that the plants produce blossoms during the winter, providing a great source of pollen when few other crops are available. Tea plants support a diversity of arthropod friends, and also a few foes. Our most commonly-observed foes in the varietal plot have been aphids and mites. Tea scale (Fiorinia theae) has been highly problematic in greenhouse production, but only seems to damage certain varieties in field plantings.
Conference Presentations & Posters:
Borden, M. and A. Dale. 2019. Susceptibility of two emerging tea crops and their ornamental congeners to tea scale, Fiorinia theae. Entomology 2019. November 17 - 20, 2019, St. Louis, MO.
Tea Genetics & Breeding
Historically, tea has been divided into two major types: China and Assam. China-type teas were first domesticated in China, have smaller leaves, are better adapted to full sun, and are generally used to make green teas. Assam-type teas were domesticated in India, have larger leaves, are shade-adapted, and are traditionally used to make black teas. These two original types have been crossed over the centuries, both intentionally and through natural hybridization, so that most modern cultivars have some mixture of the original distinctive traits. Most of the tea plants sold in the US are crosses of plants imported in the 18- and 1900s, and their progeny are not well characterized. Through our varietal trial, we have identified individual genotypes that have shown excellent field performance, and we have been working to characterize the tea plants available for purchase in the southeastern US, as a foundation to develop a breeding program for new varieties better adapted to our local growing conditions.
Publications:
Clarke, C., B.S. Richter, and B. Rathinasabapathi. 2023. Genetic and morphological characterization of United States tea (Camellia sinensis): insights into crop history, breeding strategies, and regional adaptability. Frontiers in Plant Science 14. DOI: 10.3389/fpls.2023.1149682.
Conference Presentations & Posters:
Clarke, C., B. Spakes Richter, B. Rathinasabapathi. 2021. Genetic characteristics and provenance of tea (Camellia sinensis) plants collected in the United States. Poster. ASHS Annual Meeting, Denver, CO. HortScience 56:S181.
Tea Quality
Caffeine and phenolics are compounds in tea that are associated with tea quality. Research suggests that polyphenolic compounds in green tea are also excellent antioxidants and hence are health promoting. We are using phytochemical methods to measure the levels of health promoting polyphenolic compounds and caffeine in tea grown in Florida. We aim to identify varieties and growing conditions that best maximize the compounds of interest in tea leaves which are suitable for producing excellent quality tea. This project has been partially supported by the above FDACS Specialty Crop block grant.
Conference Presentations & Posters:
Clarke, C., R. Lam, B. Spakes-Richter, B. Rathinasabapathi. 2023. Freezing as a novel method for black tea (Camellia sinensis) processing. Poster. American Society for Horticultural Science. Jul 31-Aug 4, Orlando, FL.
Clarke, C., B. Spakes-Richter, B. Rathinasabapathi. 2021. Total phenolics as an indicator of quality in Florida-grown tea. FSHS Annual Conference, Daytona Beach, FL. Proc. Fla. State Hort. Soc. 134. DOI: 10.5555/20220229146
Tea Endophytes
Endophytes are microorganisms that live inside plant tissues without causing any obvious symptoms. Some may be helpful to the plant, by producing compounds that deter pests or pathogens, while others are just using the plant for shelter, and scavenging sugars in between the plant cells. We are examining fungal endophytes of tea in an effort to (1) identify the fungi that could be considered “normal residents” of tea in Florida, (2) determine whether any of these fungi may inhibit or out-compete foliar pathogens, like the ones that cause anthracnose disease, and (3) explore the role of tea plants as an asymptomatic carrier of fungi that may cause disease on other plants.
Tea Propagation
Tea can be quite challenging to produce. Seeds are only viable for a short time, and cuttings have variable success rates, depending on variety. Undergraduate researchers in our program are working on basic questions about vegetative propagation of US tea varieties, documenting success rates for cuttings among the available stocks, and fine-tuning procedures for tissue culture propagation.
Conference Presentations & Posters:
Yue, Y., T. Campbell, B. Spakes Richter, and B. Rathinasabapathi. 2017. In Vitro methods to propagate tea (Camellia sinensis) accessions. FSHS Annual Conference, Tampa, FL. Proc. Fla. State Hort. Soc. 130:226-228.