There are many steps to consider when establishing a new southern highbush blueberry field. The purpose of this publication is to assist Florida blueberry growers with critical management practices for establishing a new field. We assume that any irrigation wells, overhead irrigation, and farm equipment are already in place. Therefore, establishing those items is not addressed here.

Blueberry production in the southeastern U.S. is challenged by various fungal diseases, especially in organic systems. Essential oils (EOs), derived from plants, offer a potential sustainable alternative to synthetic fungicides. In this study, we evaluated the in vitro and in vivo efficacy of several EOs against key blueberry fungal pathogens including Colletotrichum, Corynespora, Lasiodiplodia, and Neofusicoccum isolates. While tea tree oil showed very limited antifungal activity; thyme, oregano, savory, and cinnamon oils demonstrated varying, but promising antifungal activity against all fungal isolates in vitro. The EC50 values varied significantly across the isolates and oils, with thyme and cinnamon showing the widest ranges (up to 692 and 636 µL L⁻¹), while oregano and savory remained more consistent. In contrast, EO-based products failed to provide significant disease control compared to untreated controls in field trials. Additionally, concerns regarding phytotoxicity arose from repeated applications and higher concentrations. Other organic fungicides, such as polyoxin D zinc salt (OSO) and copper-based products, showed promise in vivo against Anthracnose, but their overall effectiveness varied. These findings highlight the complexities of translating in vitro efficacy to field performance and emphasize the need for further research to optimize the use of EOs and other organic fungicides in blueberry production.

Decomposition of plant litter, facilitated primarily by microbial decomposers, plays a critical role in biogeochemical cycling and ecosystem function. The rate of litter decomposition can determine its environmental impact, where accelerated decomposition alters the timing and rate of nutrient release and may promote nutrient leaching, whereas slowed decomposition can result in litter accumulation, which impacts seedling recruitment, fire regimes, perennation of microbial communities, and slows nutrient release. Mutualistic endophytes are known to slow litter decomposition, but less is known about the impact that plant pathogens, present in diseased litter, have on decomposition rates. We compared litter decomposition of the invasive annual grass Microstegium vimineum with Bipolaris leaf spot symptoms, a fungal disease, to litter without symptoms of the disease in a year-long common garden experiment. We found leaf tissue with disease symptoms decomposed later in the year compared to litter without symptoms. By summer, 54% of leaf tissue from healthy sites remained compared to 80% of leaf material from diseased litter. Fungal infection did not impact the lignin or C:N content of the litter. There were significant differences in fungal community composition between infected and healthy litter at the start of the experiment that persisted until the end of summer. Disease epidemics prior to senescence contributed to the persistence of infected tissue, which could slow the return of nutrients to the environmental pool and promote the survival and dispersal of pathogen inoculum the following season.

Bacterial wilt, caused by Ralstonia spp., poses a major threat to blueberry (Vaccinium corymbosum) production due to its persistence and rapid spread through soil and infected stock, highlighting the need for genetic insights to guide breeding strategies. This study investigated the genetic basis of bacterial wilt resistance in blueberry using a genome-wide association study (GWAS) across two populations comprising 401 advanced selections from the University of Florida Blueberry Breeding and Genomics Program. A high-throughput screening assay was developed to evaluate southern highbush blueberry responses to bacterial wilt based on leaf wilting severity and stem necrosis. Capture sequencing identified 38,379 single-nucleotide polymorphisms. Moderate narrow-sense heritability estimates were observed for leaf severity (0.26) and stem necrosis (0.20), and GWAS identified five small-effect quantitative trait loci on chromosomes 1, 2, 5, and 11, each explaining 4.0%-7.4% of the phenotypic variance. Candidate gene analysis revealed putative pentatricopeptide repeat (PPR), serine/threonine protein kinase, and MYB-related proteins for leaf severity, and Mlo genes and polysaccharide biosynthesis genes for stem necrosis. Genomic selection (GS) analyses demonstrated potential for improving bacterial wilt resistance, with the GS de novo GWAS approach achieving the highest predictive ability by leveraging two key markers on chromosomes 1 and 11. These results elucidate the genetic architecture of bacterial wilt resistance in blueberries and provide resources for molecular breeding strategies to enhance resistance and ensure sustainable production.

Essential oils (EOs) offer a promising natural alternative to conventional postharvest fungicides, providing enhanced food safety and reduced environmental impact while minimizing the risk of pathogen resistance. In this study, we evaluated the efficacy of thyme oil (TO) fumigation and Thyme Guard (TG) immersion for controlling brown rot in peaches. Peaches were subjected to TO fumigation or TG immersion at varying concentrations and durations, and their antifungal activity, phytotoxic effects, and cultivar-specific sensitivities were assessed. Both treatments effectively reduced postharvest lesion development, but excessive concentrations and prolonged exposure led to phytotoxicity, with distinctly different symptoms observed for fumigation and immersion. Notably, TO fumigation at 250 ppm for 24 hours and TG immersion at 0.5% for 30 s followed by 2-hour air drying at 24 °C provided optimal disease management while minimizing phytotoxicity. This study highlights the importance of pretesting EO concentrations for different cultivars to ensure safe and effective postharvest applications. Given its lower cost and superior industrial feasibility, immersion was identified as a more practical approach than fumigation. Future research should focus on integrating EO treatments with other postharvest technologies to enhance the consistency and efficacy of disease management strategies.

Hooked hair hops, aka Japanese hops, (Humulus japonicus; Cannabaceae), is an introduced invasive vine in North America. The weedy vine was observed growing on the banks of the Kentucky River (37°31′52.1″N, 83°21′04.7″W) in Breathitt County, Kentucky, USA, in September 2024 adjacent to research plots of hemp (Cannabis sativa) and Japanese stiltgrass (Microstegium vimineum). Hemp and stiltgrass are hosts of Bipolaris gigantea and showed leaf spot symptoms consistent with those previously reported (Szarka et al. 2020). Eyespot symptoms were also sporadically found on hops plants, occurring in discrete foci with low per-leaf incidence (less than 5%) and an estimated 1 to 3% disease severity on affected leaves. Symptoms on hops leaves included abundant, round, light-green to light brown colored lesions with light to dark brown borders, and sometimes surrounded by profuse tissue necrosis. Selected lesions within a pooled sample of 30 symptomatic hop leaves were dissected, surface disinfested for 30s in 10% household bleach (v/v) (7.5% sodium hypochlorite), rinsed three times in tap water, and placed on 1.5% water-agar medium for 2 days at 28°C. Large spores (macroconidia) were observed after 48h. Single spores were isolated using a dissecting needle to half-strength PDA for 5 days, and then transferred to half-strength V8 agar medium where they developed colonies with gray to dark gray mycelium and whitish tufts. Macroconidia from culture were hyaline to pale brown, contained one to four septa, and measured 171.85 to 401.7 µm × 21.5 to 35.2 µm (mean 355.8 µm x 28.3 µm, n = 80). These morphological characteristics were consistent with the description of B. gigantea (Lane et al. 2020; Szarka et al. 2023). All isolates observed had the same morphology. One representative isolate, QTH1, was selected for molecular identification of the species, and pathogenicity testing. QTH1 was grown on PDA overlaid with cellophane for 3 days at 28°C for DNA extraction. The internal transcribed spacer (ITS) region of rDNA, RNA polymerase II subunit 2 (RPB2) gene, and the partial translation elongation factor 1-α (TEF1) gene were amplified and sequenced. GenBank BLASTn analysis of all three loci showed > 98% identity with B. gigantea isolates. Sequences were deposited in GenBank under the accession of PX444436 for ITS, PX549308 for RPB2, and PX549309 for TEF1. A maximum likelihood phylogeny based on a concatenated alignment of ITS, RPB2, and TEF1 sequences confirmed the isolate as B. gigantea. To confirm pathogenicity on hops, Koch’s postulates were carried out on fully developed leaves of three plants on greenhouse-grown hops (3–4 months old) and hemp cultivar NWG2730 (6 weeks old). Plants were sprayed with 4 to 5 ml of a 5 × 10⁴ conidia/ml spore suspension, incubated for 48 h in darkness, then kept in a greenhouse (~30°C, 12-h photoperiod, 66% RH). The same lesions observed in the field developed within 13 days after inoculation (DAI) on hops, and Bipolaris leaf spot symptoms developed within 8 DAI on hemp, with conidia recovered from morphologically identical to the inoculum. Control plants inoculated with sterile water remained symptomless. This is the first report of B. gigantea causing Bipolaris leaf spot disease of hooked hair hops. The proximity of hooked hair hops to hemp cultivation highlights the potential for pathogen spillover among invasive and crop plant species, emphasizing the crucial need for effective control and management strategies to protect this valuable agricultural resource.

Botrytis cinerea is a broad host range fungal pathogen causing gray mold disease and crop losses worldwide. In blueberries, symptoms include blossom blight in the field and postharvest fruit rot, affecting the entire supply chain. With control options constrained by regulatory restrictions and fungicide resistance, the dissection of the genetic and molecular basis of blueberry response to B. cinerea can accelerate breeding for resistance. In this study, we phenotyped 354 blueberry selections using a high-throughput Botrytis infection fruit assay. The same population was genotyped by targeted sequencing for genome-wide association study (GWAS). In addition, we performed RNA-seq time-course (0-96 hours post-inoculation) for resistant and susceptible genotypes. Our results showed a continuum of tolerance levels and moderate narrow-sense heritability estimates for the disease-related traits (0.46-0.61). GWAS identified small-effect loci, consistent with quantitative resistance observed in other host plant species. Intersecting differentially expressed genes with GWAS intervals revealed eight candidate genes. Transcriptomic analyses showed that, at early stages, the resistant genotype upregulated components of basal innate immunity, including wax and cutin biosynthesis, responses to wounding and fungal-derived molecules, the MAPK cascade, and ethylene and jasmonate signaling. In contrast, susceptible genotypes displayed delayed activation of these defense pathways and altered cell wall-related processes. The moderate correlation between disease traits and wax bloom further supported a role for wax in disease response. Together, our findings provide molecular markers and candidate genes for Botrytis fruit rot resistance in blueberry with significant applications in breeding programs and opportunities to future validation studies.

Blunerviruses, family Kitaviridae, infect and cause diseases of important crop plants, including tomato, tea, and blueberry. Despite their economic importance, the epidemiology of blunerviruses and the mechanisms of plant-to-plant transmission remain largely unknown. In 2006, the blunervirus blueberry necrotic ring blotch virus (BNRBV, Blunervirus vaccinii) was detected in Florida, United States, causing disease on blueberry plants and tentatively linked to an eriophyid mite vector. To gain insights into plant-virus interaction and plant-to-plant transmission of BNRBV, in this study, we investigated sap transmission and the potential vector of blueberry-infesting eriophyid and Brevipalpus mites collected in Florida during 2022 and 2023. Although kitaviruses are vectored by several species of Brevipalpus mites, our experiments revealed a distinct vector for BNRBV. Both mite types acquired the virus, but only viruliferous eriophyids of the species Calacarus corymbosi, described for the first time in this work, transmitted the virus. Assays for BNRBV mechanical transmission were unsuccessful. This study marks the first demonstration of a characterized pathogen vectored by a mite in the genus Calacarus within kitavirus. Upon transmission by the eriophyid mite, BNRBV caused characteristic local necrotic ring blotch symptoms in blueberry leaves, and the virus was detected in symptomatic tissues and also in roots, but only at 6 months after inoculation, suggesting restricted or inefficient long-distance movement of the virus within the plant. This paper introduces a model for investigating the transmission of blunerviruses, a rapidly growing group of plant viruses.

Invasive and weedy plants proliferate in disturbed areas, including the margins of agricultural fields where they can be alternative hosts and reservoirs of crop pathogens. Research on plant pathogens focuses on economically important plants, whereas pathogens of weedy and invasive grasses are generally less well characterized. Bipolaris species have the potential to cause disease on many plant species and are common pathogens of grasses and crops in the family Poaceae. This study aimed to identify Bipolaris species causing foliar lesions on common weedy and invasive grasses in disturbed and natural areas in four counties in Florida. Isolation of characteristic Bipolaris conidia from sampled grasses resulted in 22 isolates. Maximum likelihood phylogenetic analysis of internal transcribed spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase (GPDH) gene sequences from these isolates identified four Bipolaris and one Curvularia species. B. yamadae was the most common species recovered, followed by B. sorokiniana, B. cynodontis, and B. zeae. To determine whether the Bipolaris isolates were potential crop pathogens, we tested their pathogenicity on seedlings of wheat cultivar "Jamestown." All Bipolaris isolates tested caused moderate to severe disease. Our results indicate that invasive and weedy grasses support populations of Bipolaris pathogens of crops. Knowledge of pathogen natural history can inform management of existing and emerging crop diseases.

Anthracnose, caused by Colletotrichum gloeosporioides, poses a significant threat to blueberries, necessitating a deeper understanding of the genetic mechanisms underlying resistance to develop efficient breeding strategies. Here, we conducted a genome-wide association study on 355 advanced selections of southern highbush blueberry from the University of Florida Blueberry Breeding and Genomics Program. Visual scores and image analyses were used for assessing disease severity. The population was genotyped using Capture-Seq, detecting 38,379 single nucleotide polymorphisms. The study revealed a moderate narrow-sense heritability estimate (∼0.5) for anthracnose resistance in blueberries. Minor additive loci contributing to anthracnose resistance were identified on chromosomes 2, 3, 5, 6, 9, 10, and 12, using 2 different phenotyping approaches. Visual and image-based phenotyping captured complementary aspects of anthracnose resistance, identifying distinct, non-overlapping SNP associations. Candidate gene mining flanking significant associations unveiled key defense-related proteins, such as serine/threonine protein kinases, pentatricopeptide repeat-containing proteins, E3 ubiquitin ligases that have been well-known for their roles in plant defense signaling pathways. Our findings highlight the complex and quantitative resistance mechanism for anthracnose in blueberry, providing insights for breeding strategies and sustainable disease management.

Fungi make up approximately 90% of known plant pathogens. One of the most common fungal diseases of plants is anthracnose. The name anthracnose represents a group of related fungal diseases that affect many different landscape and crop plants. This publication is intended to provide information to professional landscapers, pest control operators, Extension agents, and homeowners on how to recognize and potentially manage anthracnose diseases of landscape plants. It includes 47 images of common plants affected by the disease.

Bipolaris gigantea is a pathogen of the invasive grass Microstegium vimineum and is an emerging pathogen of other hosts such as hemp and barley, causing characteristic eyespot foliar lesions. The fungus is characterized by long pale hyaline conidia measuring approximately 300 to 350 mu m. Previously, this pathogen was classified in the Drechslera genus; it was recently reassigned as Bipolaris based on molecular identification. Here, we generated a high-quality draft genome sequence of B. gigantea isolate BGF using long- and short-read DNA sequencing. The assembled genome, 30.23 Mb in size with a Benchmarking Universal Single-Copy Orthologs (BUSCO) completeness score of 98.4%, exhibited synteny with the common grass pathogen B. sorokiniana isolate 10943. Average nucleotide identity (ANI) and single nucleotide polymorphism (SNP) analyses revealed high sequence identity with B. gigantea isolates from Cannabis sativa fields in Kentucky. This research provides a genomic resource that will contribute to future studies to understand the host range evolution and pathogenicity of this novel pathogen.Copyright (c) 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

We describe the development and release by the Florida Agricultural Experiment Station of ‘FAES 1307’ (Reg. no. CV‐298, PI 707939) and ‘FAES 1319’ (Reg. no. CV‐299, PI 707940) zoysiagrasses ( Zoysia spp. Willd.). There is increasing worldwide interest in zoysiagrasses due to their lower fertility and maintenance requirements. These two new cultivars were released based on combinations of superior turfgrass quality and density, enhanced shade tolerance, improved spring greenup and fall color, and tolerance to large patch disease (caused by Rhizoctonia solani AG2‐2 LP). Measurements of leaf length and width showed that the two new cultivars have a turfgrass texture intermediate between the coarser texture of ‘Empire’ and the very fine texture of ‘Geo’. Data from the 2013–2017 National Turfgrass Evaluation Program (NTEP) Zoysiagrass Trial showed that FAES 1319 was often ranked No. 1 or 2 out of 35 entries in the evaluations of turfgrass quality, density, and color, and usually significantly superior to the control cultivars Empire and ‘Meyer’. FAES 1307 was the top‐rated entry for sod tensile strength. Foundation stock of each cultivar will be maintained by the UF‐IFAS Agronomy Department and Florida Foundation Seed Producers.

Leaf rust is an important disease of southern highbush blueberries (SHB) in Florida and can be particularly costly in the evergreen production system. Severe leaf rust causes defoliation in the fall or early winter, which can decrease floral bud differentiation, photosynthesis, and the next season’s fruit yield. Florida blueberry growers consistently list leaf rust among their top-three disease concerns in UF/IFAS surveys. This publication will present information for Florida blueberry growers on the disease cycle, symptoms, and integrated management of this fungal leaf disease.

This publication is intended to be a resource for Florida blueberry growers to use in scouting for disease and insect/mite pest damage; managing disease, insect/mite pests, and weeds; and application of certain plant growth regulators.

Research of peach fungal gummosis (PFG), which is a vascular disease caused by fungi in the Botryosphaeriaceae family, is particularly important in the southeastern United States, southern China, South Africa, and Western Australia. This disease has been a significant concern for the peach industry in the southeastern United States since the 1970s. The changing climatic conditions in the prunus production areas of the world have worsened the severity of PFG disease. A study of the morphological and genetic profiles of Botryosphaeriaceae species from diseased peach trees found four species in Georgia, Florida, Alabama, and South Carolina. Botryosphaeria dothidea, Lasiodiplodia theobromae, Diplodia seriata, and Neofusicocoum parvum were isolated and identified using conidiospore characters and rDNA sequences of internal transcribed spacer regions and elongation factor α-1 genes. B. dothidea was the most common species from diseased peach trees. A significant implication of this research is the potential resistance in Prunus germplasm, which was genotyped for the resistance locus Botd8 and evaluated for relative susceptibility to one isolate each from B. dothidea, L. theobromae, and D. seriata. Pathogenicity evaluations of peach, almond, and interspecific hybrids used detached stem and leaf assays for susceptibility to PFG based on lesion lengths and gumming scores. L. theobromae inoculation resulted in the most extensive lesions on stems and leaves. Detached stem and leaf assays indicated that Prunus with the Botd8 locus significantly differed in lesion size when infected with B. dothidea and D. seriata. However, the resistant locus had no significant effect on the relative susceptibility of Prunus to L. theobromae. Field and detached stem and leaf assays identified almond cultivars Pioneer and Golden State and Peach × Almond hybrids with Botd8 (+) as tolerant to PFG. Correlations between detached assays and field gumming scores suggested that inoculations on detached stems or leaves under controlled conditions can be used to preliminarily screen for resistance to PFG. These detached assays for specific pathogen isolates provide an opportunity for a relatively fast, nondestructive evaluation of Prunus germplasm and are tools that can be used to identify the components of disease resistance.

Roots serve the vital function of water and nutrient uptake for plants. Healthy roots provide the foundation for productive blueberry bushes and require the right horticultural inputs and soil environment to thrive. Less-than-ideal conditions can result in unhealthy, rotten roots, sometimes caused by disease. The most common and destructive root rot disease of southern highbush blueberry (SHB) in Florida is Phytophthora root rot (PRR), caused by the oomycete pathogen Phytophthora cinnamomi Rands. Oomycetes, or “water molds,” favor water-saturated environments. The distinction between oomycetes and fungi is important for disease management, because many fungicides work for only one group, not both. Worldwide, P. cinnamomi is a devastating pathogen of approximately 5,000 woody plant host species. For blueberry growers in Florida, PRR is a persistent problem that is currently managed through careful site selection, preparation, and routine Phytophthora-specific fungicide applications.

Monilinia fructicola is a primary pathogen causing fruit brown rot of peach during pre- and postharvest in the southeast of the United States. In this in vitro study, we assessed the antifungal activity of four plant essential oil treatments against five isolates of M. fructicola obtained from naturally infected peaches in Florida, Georgia, and South Carolina. The tested essential oils were white thyme oil, oregano oil, summer savory oil, and a 1:1 mixture of thyme and oregano oils. We evaluated isolates’ growth using a Gompertz growth curve model. All tested essential oils exhibited antifungal activity against all isolates, with thyme, oregano, and the 1:1 mixture of thyme and oregano oils showing no significant differences and no evidence of synergy. Savory oil showed the least effectiveness and stability of the four essential oil treatments. We observed diverse sensitivities of different M. fructicola isolates to the essential oils. The minimum inhibitory concentration values for the essential oils ranged from 200 to 500 μl/liter, and the minimum fungicidal concentration values varied from 500 to 750 μl/liter, depending on the fungal isolate and essential oil treatment. All isolates were inhibited by the essential oils at 500 μl/liter and killed at 750 μl/liter. Our findings provide a basis for future in vivo research on the use of these essential oils for controlling fruit brown rot caused by M. fructicola in peach postharvest handling. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

'FSA1602' (Reg. no. CV-294, PI 704119) hybrid St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze] was developed and released by the Florida Agricultural Experiment Station, University of Florida, in 2018. FSA1602 has a distinct olive blue-green color and high levels of resistance to gray leaf spot, take-all root rot, and excellent shade tolerance and turfgrass quality (TQ). It is targeted for use in residential and commercial lawns in the southern United States. FSA1602 has coarse textured leaves similar in width to 'Floratam' and leaf lengths similar to 'SS-100' (Palmetto) but shorter than Floratam. FSA1602 stolon width is larger than Floratam or Palmetto but has a mean stolon internode length shorter than either Floratam or Palmetto. It produces a dense turfgrass with high TQ that is similar to or better than Floratam and with less winter kill than Floratam, which is the most widely used St. Augustinegrass for lawns in Florida. 'FSA1602' has a distinct olive blue-green color with coarse leaves and excellent resistance to gray leaf spot.'FSA1602' is adapted for use throughout the southern regions of gulf coast states.'FSA1602' is commercialized as 'CitraBlue' St. Augustinegrass.

The pathogen Xylella fastidiosa is a xylem-restricted, gram-negative bacterium that is known to cause diseases of many cultivated plant species. Recent outbreaks of X. fastidiosa diseases in Europe have brought attention to the impact of this pathogen, especially to perennial crops. Among the Prunus genus, X. fastidiosa is known to have a wide range of hosts, including plum, almond, peach, cherry, and apricot. Infected trees have reduced fruit quality, possibly resulting in unmarketable fruits, as well as reduced lifespan. There are no curative management options for X. fastidiosa diseases in Prunus ; therefore, development of resistant or tolerant cultivars through breeding represents an efficient option to reduce the impact of this pathogen. In this context, the main objective of this study was to determine the occurrence of X. fastidiosa in germplasm of the Stone Fruit Breeding Program at the University of Florida located in Gainesville, FL, USA, under natural infection conditions. A total of 43 individuals representing 10 different genotypic groups within the Prunus genus were tested for the presence of X. fastidiosa . Additionally, we report a novel and easy sampling method using sawdust collected from tree trunks for the detection of this pathogen in Prunus and the development of an endogenous control for improving the diagnosis of this pathogen using real-time polymerase chain reactions. Our results showed a high incidence of X. fastidiosa in the germplasm tested, with more than 65% of the samples positive for the presence of the bacterial pathogen. However, X. fastidiosa was not detected in most of the P. mume samples tested, whereas almost all the P. mume × P. armeniaca hybrids were positive. Negative individuals were also identified in P. avium , P. campanulata , P. umbellata , and P. salicina × P. ceracifera. These trees have been planted in the field, exposed to natural infection for 4 to 11 years, and are considered to show field resistance. Finally, primers and probes based on the Prunus COX gene developed in this study can be used as an internal amplification control to enhance the interpretation of results of X. fastidiosa detection assays using sawdust samples.