The Disease Triangle of Chestnut: A review of host, pathogen, and environmental interactions of chestnuts cultivated in the eastern United States.

Chestnuts, the edible seeds of the genus Castanea, are a perennial food crop closely tied to the global migration of humans throughout history and have recently been gaining popularity in agriculture and forest restoration in eastern North America. Cultivation of chestnuts yields nutritionally balanced food while fostering economic development, food security, and environmental health. However, diseases and insect pests threaten successful ecological restoration and food production. In this review we explore conditions affecting chestnuts in the eastern United States through the lens of the disease triangle. A "host" in the disease triangle is not merely a single tree, but a tree including its constituent population of fungal endophytes. Chestnut trees are rich with microbial life, and the sustainability of chestnuts in forest and cultivated settings may lie in understanding and manipulating microbial communities to improve plant health and control destructive diseases. To benefit from the ecological and economic potential of chestnuts on the landscape, it may be necessary to select locally adapted chestnut trees, regardless of pedigree, that are resilient against cosmopolitan pathogens. With transport of plants and pathogens throughout the globe, and with landscape level environmental changes over the last century, chestnut trees in the eastern United States (U.S.) are in a unique disease landscape compared to their ancestors. Diseases of economic concern from fungi and fungal-like organisms include chestnut blight (Cryphonectria parasitica) and ink disease (Phytophthora cinnamomi) on American and European chestnuts, oak wilt (Bretziella fagacearum) on all chestnut species, and the emerging diseases of brown rot (Gnomoniopsis smithogilvyi) and chestnut anthracnose (Colletotrichum henanense). The eastern U.S. has experienced profound environmental changes over the 20th century and into the early 21st century. These changes happen to coincide with the demise of the American chestnut in the eastern forest, efforts to re-establish chestnut as a forest species, and the rise in cultivation of multiple chestnut species and hybrids as a culinary crop. Chestnut trees growing in the early 21st century face different environmental circumstances than the American chestnuts of pre-colonial times, including changes in forest composition, rainfall changes and acidification, industrialized agriculture's increased chemical inputs, rising global temperatures, and increased levels of carbon dioxide in the atmosphere. We conclude that chestnut tree species for both forestry and agriculture should be considered based on current fitness, adaptability, and economic and ecological value considering continued dynamics in host and pathogens distributions and anthropogenically driven climatic and edaphic conditions.

Effectiveness of Chemical Sanitizers against Salmonella Typhimurium in Nutrient Film Technique (NFT) Hydroponic Systems: Implications for Food Safety, Crop Quality, and Nutrient Content in Leafy Greens.

Hydroponic farming systems play an increasingly important role in the sustainable production of nutrient-rich foods. The contamination of surfaces in hydroponic fresh produce production poses risks to the food safety of crops, potentially endangering public health and causing economic losses in the industry. While sanitizers are widely used in commercial hydroponic farms, their effectiveness against human pathogens on surfaces and their impact on plant health and quality are not known. In this study, we evaluated the efficacy of chemical sanitizers in eliminating Salmonella Typhimurium from inanimate surfaces in commercial hydroponic Nutrient Film Technique (NFT) systems. Further, we assessed the impact of sanitizers on the yield, quality, and nutritional value of lettuce and basil. Sanitizers (Virkon, LanXess, Pittsburgh, PA, USA; SaniDate 12.0, BioSafe Systems, East Hartford, CT, USA; KleenGrow, Pace Chemical Ltd., Delta, BC, Canada; Green Shield, United Labs Inc., St Charles, IL, USA; Zerotol, BioSafe Systems, East Hartford, CT, USA; Bleach, Pure Bright, ON, Canada) were tested against Salmonella Typhimurium inoculated on NFT surfaces (nutrient reservoir, growing channels, top covers, drain lines). The effective treatments were then tested for their impact on lettuce and basil in a split-plot experiment conducted in commercial NFT units. Crop yield, color, and nutrient content (chlorophyll and carotenoids) were measured throughout the crop life cycle. While all quaternary ammonium compounds (QAC), SaniDate 12.0 (200 ppm), Zorotol (5%), and Virkon (1%) eliminated Salmonella Typhimurium from commercial NFT surfaces, chlorine-based sanitizer treatments were statistically similar to water treatments on most surfaces. All chemical sanitizers impacted the yield, color, and nutritional value of lettuce and basil. SaniDate 12.0 (200 ppm) was the least detrimental to crops and was identified as a potential candidate for further validation in commercial hydroponic settings. The findings of this study will be translated into recommendations for the industry and will contribute to the development of future food safety guidelines and policies.

Cultivating Food Safety Together: Insights About the Future of Produce Safety in the U.S. Controlled Environment Agriculture Sector.

Controlled environment agriculture (CEA) is a rapidly growing sector that presents unique challenges and opportunities in ensuring food safety. This manuscript highlights critical gaps and needs to promote food safety in CEA systems as identified by stakeholders (n=47) at the Strategizing to Advance Future Extension andResearch (S.A.F.E.R.) CEA conference held in April 2023 at The Ohio State University's Ohio CEA Research Center. Feedback collected at the conference was analyzed using an emergent thematic analysis approach to determine key areas of focus. Research-based guidance is specific to the type of commodity, production system type, and size. Themes include the need for improved supply chain control, cleaning, and sanitization practices, pathogen preventive controls and mitigation methods and training and education. Discussions surrounding supply chain control underscored the significance of the need for approaches to mitigate foodborne pathogen contamination. Effective cleaning and sanitization practices are vital to maintaining a safe production environment, with considerations such as establishing standard operating procedures, accounting for hygienic equipment design, and managing the microbial communities within the system. Data analysis further highlights the need for risk assessments, validated pathogen detection methods, and evidence-based guidance in microbial reduction. In addition, training and education were identified as crucial in promoting a culture of food safety within CEA. The development of partnerships between industry, regulatory, and research institutions are needed to advance data-driven guidance and practices across the diverse range of CEA operations and deemed essential for addressing challenges and advancing food safety practices in CEA. Considering these factors, the CEA industry can enhance food safety practices, foster consumer trust, and support its long-term sustainability.

Lettuce Contamination and Survival of Salmonella Typhimurium and Listeria monocytogenes in Hydroponic Nutrient Film Technique Systems.

Hydroponic vegetable production is increasing globally, but there is a lack of science-based recommendations to ensure their food safety. Specifically, there is limited evidence for establishing water management strategies. The purpose of this study was to determine the survival of Salmonella Typhimurium and Listeria monocytogenes in commercial nutrient flow technology (NFT) systems during the lifecycle of lettuce exposed to sporadic or extreme contamination. NFT systems were inoculated with Salmonella Typhimurium or Listeria monocytogenes, and nutrient solution, rockwool, roots, and lettuce leaves were collected over the lettuce production cycle for pathogen enumeration and detection. Both human pathogens persisted in the lettuce NFT growing system throughout the growth cycle of lettuce. Salmonella Typhimurium and L. monocytogenes accumulated in rockwool medium and on lettuce roots and were transferred to the leaves at quantifiable levels from the contaminated nutrient solution. In the nutrient solution, Salmonella concentration under sporadic and extreme conditions declined significantly 24 h after inoculation and again 7 days post-inoculation (p < 0.0001). Under extreme conditions, the concentration did not change significantly after 7 days, while under sporadic conditions, the concentration declined again 14 days post-inoculation in the nutrient solution collected from the reservoirs. L. monocytogenes populations in the nutrient solution fluctuated significantly over the 28-day growth cycle (p < 0.0001). Under extreme conditions, L. monocytogenes concentrations in the nutrient solution declined, while under sporadic conditions, the populations increased. The findings of this study, for the first time, describe human pathogen survival in commerical NFT systems and highlight the urgent need for novel approaches to mitigating the risks from nutrient solution contaminaiton in hydroponics.

First Report of Neopestalotiopsis Disease in Ohio caused by an emerging and novel species of Neopestalotiopsis on Strawberry.

In October 2021, strawberry (Fragaria x ananassa) plants (cv. Ruby June) that had dark brown lesions with a diffuse black halo and light brown center and / or dark brown V-shaped necrotic areas often starting from the edge of the leaves were observed in a commercial planting in Washington County. The grower reported 50% incidence in the field when the sample was first submitted and two weeks later reported 80% incidence. The morphology of conidia present on symptomatic leaf tissue was consistent with species of Neopestalotiopsis (Maharachchikumbura et al. 2014). The conidia were ellipsoid to fusiform, five-celled, with three light brown colored median cells and one hyaline apical and basal cell. The apical cells had two to four flexuous appendages and the basal cell had one non-flexuous appendage. Average (N=30) conidia length, not including the appendages, and width was 24.1 ± 2.7 and 6.5 ± 1.4 µm respectively. Two isolates (MLI267-21 and MLI268-21) were purified on potato dextrose agar, producing a dense white mycelial mat with undulate margins. The underside color of the mycelial mat was pinkish-orange. Conidiomata formed randomly in the colonies and extruded black gelatinous spores. To confirm the identity of these isolates the genome of MLI267-21 was sequenced using the NextSeq 2000 Illumina platform and Nextera DNA CD indexes (OSU Applied Microbiology Service Laboratory, Columbus, OH). Partial internal transcribed spacer (ITS) region, ß-tubulin (TUB), and translation elongation factor 1-alpha (TEF-1α) gene sequences (Accession numbers: OM649904, OM649905, and OM649906 respectively) were extracted from the MLI267-21 genome, concatenated, and aligned to published reference sequences. These same genes were amplified and sequenced from MLI268-21. Maximum likelihood phylogenetic analysis performed in IQ-TREE (Minh et al. 2020, Kalyaanamoorthy et al. 2017, Chernomor et al. 2016) with the aligned sequences revealed the clustering of MLI267-21 and MLI268-21 with seven other Neopestalotiopsis isolates, from strawberry (17-43L; Baggio et al. 2021) and pomegranate (GEV3426 to GEV3431; Xavier et al. 2021) leaves in Florida, which form a unique and emerging species group. The ITS, TUB, and TEF-1α sequences from both Ohio isolates were 100% similar to the same sequences from 17-43L and GEV3426 - GEV3431. Pathogenicity tests were performed using MLI267-21 by spray inoculating (~104 spore/ml) four-week-old 'Cabrillo' strawberry plants (n=4) and placing three drops (10µl each) of spore suspension (~104 spore/ml) on the calix area of detached fruit (n=4). Non-inoculated plants and fruit (n= 4 each) served as negative controls. The plants were covered with transparent plastic bags and maintained at 25 °C for 72 hours before the bags were removed (Baggio et al. 2021). Five days post-inoculation, dark brown circular spots on the leaves and petioles were observed on all four inoculated plants and acervuli were observed within the necrotic spots after an additional 72 hours in a moist chamber. Fruits were incubated in a moist chamber at 25 °C and after 72 hours orange-brown lesions formed on the fruit. After five days, fruit were mushy and covered with white mycelia, acervuli, and conidiomata. Neopestalotiopsis disease has been reported on strawberry in Florida (Baggio et al. 2021) and in several South American (Obregon et al. 2018, Hidrobo et al. 2021) and European (Chamorro et al. 2016, Gilardi et al. 2019) countries. The disease can cause rapid plant death when conditions are warm and wet. Research to investigate host susceptibility and to identify effective chemical and biological control has been initiated in Ohio to establish preventative management programs for commercial field operations.

First report of Colletotrichum henanense causing anthracnose on Chinese chestnut in the United States.

Culinary chestnut production in the United States (US) is a rapidly growing industry supporting fresh market and value-added industries. An estimated 200-400 new acres of chestnuts are planted every year in the US, with most growers east of the Rocky Mountains planting Chinese chestnut (Castanea mollissima) or Chinese chestnut hybrids. In 2018, Ohio producers of Chinese chestnut reported losses of up to 80% to blossom end rot. Symptoms were like those reported by Fowler and Berry (1958), including black spots on the chestnut shell, often at the stylar end, and blackening of the kernels. Spots covered 1-100% of the kernel, however, no signs of any pathogen were present on the shell or kernel. In 2020, cankers that were brown/black in color, sunken, and ~1 cm in length were observed on 1-yr twigs of chestnut seedlings from a nursery operation on the same farm from which the symptomatic kernels were observed. In some seedlings, distal portions of the twigs died, while in other seedlings only shoots and leaves within the cankered areas died. Black acervuli were observed erupting from the cankers. Colletotrichum spp. were isolated and cultured on potato dextrose agar from surface-sterilized tissue from kernel lesions (MLI246-21 to MLI249-21) and twig cankers (MLI250-21 and MLI251-21). All isolates produced grey aerial mycelia, pink sporodochia, and cylindrical conidia with rounded ends ranging in size from 12-20 um long by 5-8 um wide. Isolates were preliminarily identified as belonging to the Colletotrichum gloeosporioides species complex (CGSC). The glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene, ß-tubulin (TUB2) gene, and the intergenic spacer ApMat were amplified from genomic DNA and sequenced (Dowling et al. 2020). These genes are suitable for identifying species within the CGSC (Eaton et al. 2021). Sequences were submitted to the GenBank database (GAPDH OL687148 to OL687153, TUB2 OL741624 to OL741629 and ApMAT OL695914 to OL695919). BLASTn queries of NCBI GenBank showed that the GAPDH, TUB2, and ApMat sequences from all isolates had 98%, 98% and 99% identity with C. henanense isolates MT513015.1, MT513080.1, and MT512917.1 from apple (Martin et al. 2021). Representative isolates were used to demonstrate Koch's postulates and confirm pathogenicity on kernels (MLI246-21 and MLI249-21) and twigs (MLI250-21). Developing chestnuts in burs (n=4 per isolate) were gathered from the field and surface-sterilized with 70% ethanol. Nuts (n=12 per isolate) inside burs were inoculated by injecting 50uL of inoculum (~1.0 x 106 conidia/mL) directly into each kernel with a hypodermic needle and sterile syringe. Burs were incubated at room temperature in a moist chamber for 14 days. One-year-old seedlings (n=6) grown in containers were used for twig inoculations. Twig nodes (one/seedling) were surface sterilized with 70% ethanol and inoculated by wounding the stem with a sterile probe and dropping 100uL of inoculum into each wound. Seedlings were incubated in a glass house for 60 days and monitored daily for symptom development. Nuts (n=9) and twigs (n=3) were inoculated with sterile water using the same inoculation and incubation conditions to serve as negative controls. Inoculated kernels developed characteristic brown/black lesions at the wound site and inoculated twigs developed brown/black, slightly sunken cankers with acervuli. No symptoms developed on the control kernels or twigs. Fungi with the same colony, conidial, and molecular characteristics as C. henanense were re-isolated from inoculated kernels and twigs. Blossom end rot caused by Glomerella cingulata has been reported on chestnut kernels in Georgia (Fowler and Berry 1958), but this is the first report of C. henanense causing rot on kernels and twigs in the US. Since 2018, C. henanense has been isolated from infected nuts received from commercial orchards in Pennsylvania, Missouri, and Alabama. We propose to retire the name "blossom end rot" for the symptoms found in kernels and replace it with the name "chestnut anthracnose" for this disease that affects both twigs and kernels of Chinese chestnut.

Postharvest Survival of Porcine Sapovirus, a Human Norovirus Surrogate, on Phytopathogen-Infected Leafy Greens.

Leafy greens are increasingly being recognized as an important vehicle for human noroviruses (HuNoV), which cause recurring gastroenteritis outbreaks. Leafy greens often become infected by phytopathogens in the field, which may cause symptoms on the edible parts. Whether plant pathogen infections enhance the survival of HuNoV on leafy greens is unknown. Lettuce and spinach plants were infected with a bacterium, Xanthomonas campestris pv. vitians strain 701a, and with Cucumber mosaic virus strain Fny, respectively. The survival rate of porcine sapovirus (SaV), a HuNoV surrogate, on infected and noninfected postharvest leaves was then assessed. In addition, acibenzolar-S-methyl, a commercial chemical elicitor of plant systemic defense, was used to assess whether stimulating the plant host defense affects the postharvest survival of SaV. Leaves harvested from control and treated plants were inoculated with SaV and incubated for 7 days at 4°C. The infectivity (tissue culture infectious dose affecting 50% of the culture [TCID50]/ml) and RNA (genomic equivalent/ml) titers of SaV were assayed using immunohistochemistry staining and SaV-specific TaqMan real-time reverse transcription PCR. Our results showed that cucumber mosaic virus Fny induced mild, nonnecrotic symptoms on spinach leaves and had no effect on SaV survival. In contrast, X. campestris pv. vitians 701a induced small localized necrotic lesions and significantly enhanced SaV survival on lettuce leaves. Treatment with acibenzolar-S-methyl was effective in reducing X. campestris pv. vitians 701a-induced lesions on infected lettuce plants but had no direct effect on SaV survival when used on healthy lettuce plants. These findings indicate that phytopathogen-induced necrotic lesions may enhance the postharvest survival of HuNoV on lettuce leaves. Therefore, preventive measures aiming to maintain healthy plants and minimize preharvest biological damage are expected to improve the safety of leafy greens.

Use of the vital stain FUN-1 indicates viability of Phytophthora capsici propagules and can be used to predict maximum zoospore production.

The fluorescent vital dye FUN®-1 (2-chloro-4-[2,3-dihydro-3-methyl-{benzo-1,3-thiazol-2-yl}-methylidene]-1-phenylquinolinium iodide) was evaluated as a tool to assess Phytophthora capsici sporangia and zoospore metabolic activity and viability. Under aerobic conditions, mycelia, sporangia and zoospores cultured on agar medium and stained with FUN-1 exhibited red fluorescent cylindrical intravacuolar structures (CIVS) that were clearly visible at 100× magnification. Encysted zoospores did not exhibit CIVS after exposure to FUN-1 dye. Over 7 d there was a significant reduction in the percent of sporangia containing CIVS, which corresponded with a significant increase in zoospore formation and release. The decline in the percentage of metabolically active sporangia and increase in the number of zoospores fit both a linear and log regression model. The FUN-1 dye was suitable for distinguishing between live and dead sporangia and effective in monitoring the change in metabolic activity of sporangia over time. It will be useful in determining parameters, including P. capsici culture age, that maximize production of zoospores in vitro.

Leveraging management strategies for seedborne plant diseases to reduce Salmonella enterica Serovar Typhimurium incidence on tomato seed and seedlings.

Tomatoes have been linked to many outbreaks of salmonellosis over the last decade, but the routes of contamination have yet to be discerned. Many phytopathogens of tomato are seedborne and are effectively managed using seed sanitizers. Seed sanitizers effective against bacterial phytopathogens were evaluated for their efficacy in killing bioluminescent Salmonella enterica serovar Typhimurium strain SeT-A14 on tomato seed infested with moderately high and high levels of pathogen. SeT-A14 incidence on seedlings produced from contaminated seed following sanitation was also determined. At a moderately high infestation rate (40%), SeT-A14 was eradicated on seed sanitized with 1.2% sodium hypochlorite (NaClO) mixed with 0.03% surfactant for 2 min, hydrochloric acid (HCl) for 30 min, and trichloromelamine for 2 min. At a higher infestation rate (94%), only NaClO and HCl were effective in eradicating SeT-A14 from the seed. At both infestation rates, 2% Virkon-S for 15 min significantly reduced SeT-A14 incidence compared with the nontreated infested controls but did not eradicate the pathogen. Hot water, a commonly used sanitizer for managing seedborne bacterial plant diseases, significantly reduced SeT-A14 on heavily infested seed, but incidence was still moderate at 17.5%. On seedlings produced from moderately highly infested seed, SeT-A14 was not detected using RapidChek Salmonella test strips. Using heavily infested seed, SeT-A14 was detected with the test strips in one of four pooled samples of 14-day-old seedlings produced from nonsanitized seed and from seed sanitized with hot water and trichloromelamine. However, bioluminescence was not observed on 14-day-old seedlings. To our knowledge, this is the first report that provides evidence that S. enterica serovar Typhimurium can be seed transmitted and can lead to the contamination of tomato seedlings. In addition to eliminating important bacterial phytopathogens from tomato seed, NaClO or HCl may mitigate the risk of Salmonella seedling contamination.

Novel Phakopsora pachyrhizi extracellular proteins are ideal targets for immunological diagnostic assays.

Phakopsora pachyrhizi, the causal agent of Asian soybean rust (ASR), continues to spread across the southeast and midsouth regions of the United States, necessitating the use of fungicides by producers. Our objective in this research was to identify ASR proteins expressed early during infection for the development of immunodiagnostic assays. We have identified and partially characterized a small gene family encoding extracellular proteins in the P. pachyrhizi urediniospore wall, termed PHEPs (for Phakopsora extracellular protein). Two highly expressed protein family members, PHEP 107 and PHEP 369, were selected as ideal immunodiagnostic targets for antibody development, after we detected PHEPs in plants as early as 3 days postinfection (dpi). Monoclonal antibodies (MAbs; 2E8E5-1 and 3G6H7-3) generated against recombinant PHEP 369 were tested for sensitivity against the recombinant protein and extracts from ASR-infected plants and for specificity against a set of common soybean pathogens. These antibodies should prove applicable in immunodiagnostic assays to detect infected soybeans and to identify ASR spores from sentinel surveillance plots.

A Polymerase Chain Reaction Assay for the Detection of Xanthomonas campestris pv. musacearum in Banana.

Polymerase chain reaction (PCR) primers (BXW-1 and BXW-3) for conventional PCR were developed from conserved sequences in the hrpB operon of the hrp gene cluster from Xanthomonas campestris pv. musacearum, the causative agent of banana Xanthomonas wilt (BXW). All 50 strains of X. campestris pv. musacearum, isolated from Uganda, Rwanda, and Tanzania, produced a 214-bp amplicon when whole cells, bacterial ooze from infected tissue, and genomic DNA purified from bacterial ooze or infected tissue were used as template. The BXW primers also detected strains of X. axonopodis pv. vasculorum isolated from sugarcane and maize and strains of X. vasicola pv. holcicola isolated from sorghum. All of the strains of X. campestris pv. musacearum were clonal when compared using enterobacterial repetitive intergenic consensus PCR.

Resistance in Lycopersicon esculentum Intraspecific Crosses to Race T1 Strains of Xanthomonas campestris pv. vesicatoria Causing Bacterial Spot of Tomato.

ABSTRACT We used molecular markers to identify quantitative trait loci (QTL) that confer resistance in the field to Xanthomonas campestris pv. vesicatoria race T1, a causal agent of bacterial spot of tomato. An F(2) population derived from a cross between Hawaii 7998 (H 7998) and an elite breeding line, Ohio 88119, was used for the initial identification of an association between molecular markers and resistance as measured by bacterial populations in individual plants in the greenhouse. Polymorphism in this cross between a Lycopersicon esculentum donor of resistance and an elite L. esculentum parent was limited. The targeted use of a core set of 148 polymerase chain reaction-based markers that were identified as polymorphic in L. esculentum x L. esculentum crosses resulted in the identification of 37 markers that were polymorphic for the cross of interest. Previous studies using an H 7998 x L. pennellii wide cross implicated three loci, Rx1, Rx2, and Rx3, in the hypersensitive response to T1 strains. Markers that we identified were linked to the Rx1 and Rx3 loci, but no markers were identified in the region of chromosome 1 where Rx2 is located. Single marker-trait analysis suggested that chromosome 5, near the Rx3 locus, contributed to reduced bacterial populations in lines carrying the locus from H 7998. The locus on chromosome 5 explained 25% of the phenotypic variation in bacterial populations developing in infected plants. An advanced backcross population and subsequent inbred backcross lines developed using Ohio 88119 as a recurrent parent were used to confirm QTL associations detected in the F(2) population. Markers on chromosome 5 explained 41% of the phenotypic variation for resistance in replicated field trials. In contrast, the Rx1 locus on chromosome 1 did not play a role in resistance to X. campestris pv. vesicatoria race T1 strains as measured by bacterial populations in the greenhouse or symptoms in the field. A locus from H 7998 on chromosome 4 was associated with susceptibility to disease and explained 11% of the total phenotypic variation. Additional variation in resistance was explained by plant maturity (6%), with early maturing families expressing lower levels of resistance, and plant habit (6%), with indeterminate plants displaying more resistance. The markers linked to Rx3 will be useful in selection for resistance in elite x elite crosses.

Identification and Management of Colletotrichum acutatum on Immature Bell Peppers.

Farmers in northwestern Ohio reported severe losses due to anthracnose in immature (green) bell pepper as early as 1998. Two fungal isolates (AN1 and AN2) were recovered from immature fruit showing severe anthracnose symptoms. The pathogen was identified as Colletotrichum acutatum based on morphological and cultural characteristics, polymerase chain reaction (PCR) assay with the C. acutatum species-specific primer (CaInt2), and nucleotide sequencing. Isolate AN1 was pathogenic on immature pepper, tomato, and strawberry. Twenty-two bell pepper cultivars evaluated in field trials were all susceptible to C. acutatum AN1 and AN2, but the degree of susceptibility varied among cultivars. 'Crusader', 'Valiant', and 'ACX229' were the most susceptible, while 'North Star' and 'Paladin' were least susceptible. The fungicides pyraclostrobin (Cabrio) alternated with manganese ethylenebisdithiocarbamate (Manex), chlorothalonil (Bravo Ultrex) alone, Manex plus copper hydroxide (Kocide 2000), and pyraclostrobin + boscalid (BAS 516 = Pristine) alternated with Manex significantly reduced anthracnose incidence and intensity in bell peppers compared with the untreated control.