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California has been invaded by two distinct Euwallacea spp. that vector unique plant pathogenic symbiotic fungi on multiple hosts and cause Fusarium dieback. The objective of this study was to develop multiplex real-time quantitative PCR assays using hydrolysis probes targeting the β-tubulin gene to detect, distinguish, and quantify fungi associated with the polyphagous shot hole borer (PSHB; Euwallacea whitfordiodendrus, Fusarium euwallaceae, Graphium euwallaceae, and Paracremonium pembeum) as well as the Kuroshio shot hole borer (KSHB; Euwallacea kuroshio, Fusarium kuroshium, and Graphium kuroshium) from various sample types. Absolute quantification reaction efficiencies ranged from 88.2 to 104.3%, with a coefficient of determination >0.992 and a limit of detection of 100 copies µl-1 for all targets across both assays. Qualitative detection using the real-time assays on artificially inoculated avocado shoot extracts showed more sensitivity compared with conventional fungal isolation from wood. All symbiotic fungi, except P. pembeum, from PSHB and KSHB female heads were detectable and quantified. Field samples from symptomatic Platanus racemosa, Populus spp., and Salix spp. across 17 of 26 city parks were positively identified as PSHB and KSHB through detection of their symbiotic fungi, and both were found occurring together on five trees from three different park locations. The molecular assays presented here can be utilized to accurately identify fungi associated with these invasive pests in California.

Shot hole borer (SHB)-Fusarium dieback (FD) is a new pest-disease complex affecting numerous tree species in California and is vectored by two distinct, but related ambrosia beetles (Euwallacea sp. nr. fornicatus) called polyphagous shot hole borer (PSHB) and Kuroshio shot hole borer (KSHB). These pest-disease complexes cause branch dieback and tree mortality on numerous wildland and landscape tree species, as well as agricultural tree species, primarily avocado. The recent discovery of KSHB in California initiated an investigation of fungal symbionts associated with the KSHB vector. Ten isolates of Fusarium sp. and Graphium sp., respectively, were recovered from the mycangia of adult KSHB females captured in three different locations within San Diego County and compared with the known symbiotic fungi of PSHB. Multigene phylogenetic analyses of the internal transcribed spacer region (ITS), translation elongation factor-1 alpha (TEF1-α), and RNA polymerase II subunit (RPB1, RPB2) regions as well as morphological comparisons revealed that two novel fungal associates Fusarium kuroshium sp. nov. and Graphium kuroshium sp. nov. obtained from KSHB were related to, but distinct from the fungal symbionts F. euwallaceae and G. euwallaceae associated with PSHB in California. Pathogenicity tests on healthy, young avocado plants revealed F. kuroshium and G. kuroshium to be pathogenic. Lesion lengths from inoculation of F. kuroshium were found to be significantly shorter compared with those caused by F. euwallaceae, while no difference in symptom severity was detected between Graphium spp. associated with KSHB and PSHB. These findings highlight the pest disease complexes of KSHB-FD and PSHB-FD as distinct, but collective threats adversely impacting woody hosts throughout California.

Fungal trunk pathogens are a growing global issue, significantly affecting fruit and nut tree crop cultivation. These pathogens, mainly ascomycetes, belong to several families including Botryosphaeriaceae, Calosphaeriaceae, Cytosporaceae, Diaporthaceae, Diatrypaceae, Nectriaceae and Togniniaceae. The large number of species involved represent a challenge in clarifying the etiology of trunk diseases, further complicated by frequent co-infections of different fungi. Typically, these pathogens enter plants through wounds and natural openings, and some can persist in a latent phase, switching to pathogenicity under favorable conditions. This aspect represents a significant concern for both nurseries and orchards. Moreover, the current climatic conditions and the intensification of cropping systems are likely exacerbating the spread and development of these pathogens, making their management more difficult. This review provides an overview of the main ascomycetes causing trunk diseases, discussing their identification, characterization, and detection methods. Accurate identification and characterization are crucial to increase the knowledge on these pathogens and to develop effective management strategies. An insight on the current preventive and curative strategies is provided as well to explore sustainable crop protection strategies, including agronomic practices, biological control, the use of new active ingredients and tolerant and/or resistant cultivars, to address this escalating problem.

Black oat ( Avena strigosa Schreb.) is used as a cereal crop, forage crop or green manure in temperate regions. In Japan, it is mainly cultivated in Hokkaido island and, because of the vigorous initial growth and ability to suppress the proliferation of plant pathogenic nematodes (Uesugi et al. 2018), its use is recently increasing. In November 2021, a leaf spot and blight disease was observed in the grass cultivated in Kitahiroshima city (N43°0, E141°31). At first, blackish brown spindle-shaped or elliptical lesions, about 3 to 5 × 1 to 2 mm were formed on leaves, and they expanded by forming yellowish-brown halos around them, eventually resulting in leaf blight later on (Fig.1), damaging 5-10 % of leaf area, varied by cultivar. The lesions were excised, surface-sterilized, and incubated on water agar under near-UV light. Three single-spore isolates of Pyrenophora -like fungus were obtained from the lesions and deposited at the NIAS Genebank, Japan (https://www.gene.affrc.go.jp/index_en.php) as MAFF511692, 511693 and 511694. The sequences of ribosomal RNA gene (rDNA) and its internal transcribed spacer (ITS), and the gpd sequences of the isolates were analyzed as described by Marin-Felix et al. 2019. The rDNA-ITS sequences (GenBank accession no. LC769170, LC769171 and LC769172) of the isolates matched with that of the ex-type strain of Pyrenophora avenicola (MK539972) isolated from Avena seed. The sequences of the gpd (accession no. LC795722, LC795723 and LC795724) matched well with that of the ex-type strain (MK540180). Conidiophores of the isolates were septate, straight or flexuous, pale brown to olivaceous brown, 81.4 to 125.7 × 4.2 to 6.5 (ave. 106.4×5.7µm, n=50) µm, with hyaline vegetative hyphae (Fig.2). Conidia were slightly verrucose, cylindrical to obclavate, pale brown to olivaceous brown, 42.2 to 78.5 × 9.0 to 13.3 µm (ave. 56.9 ×10.4µm, n =50) and 2 to 7 distoseptate. This description overlap with the original description of P. avenicolai (Marin-Felix et al. 2019) and the leaf spot pathogen of Avena sativa reported in China (Chen et al. 2022). The fungus was identified as P. avenicola on the basis of morphology and molecular phylogenetic analysis. To produce inoculum, the isolate MAFF511692 was grown on V8 juice agar at 25°C under near-UV light for 7 days. Five plants each of cv. 'Soil saver', 'New oats' of A. strigosa (Kaneko seeds co.) and 'New almighty' of A. sativa (Snow brand seed co.) were grown in a greenhouse for approximately 14 days and then inoculated by atomizing them with the conidial suspension (10 4 conidia/ml) at the five-leaf stage. Five plants of each cultivar sprayed with sterilized distilled water served as the control. Inoculated plants were covered with plastic bags for 24 h at 25°C. After 5 days, blackish brown elliptical lesions developed on the leaves of all inoculated plants of both cultivars of A. strigosa (Fig. 3) and A. sativa , implying broad pathogenicity of the fungus to species and cultivars of Avena plants. Halo was not observed, maybe due to fewer stress in the greenhouse environment. Controls remained asymptomatic. The produced lesions were incubated as described above and the reisolated fungus was identified as P. avenicola based on the morphology, confirming Koch's postulates. To our knowledge, this is the first report of leaf blight caused by P. avenicola on black oat in Japan.

Panicle blast, caused by Magnaporthe oryzae , is a destructive disease of rice worldwide. Clarifying the susceptibility of rice panicles at different stages is of great significance for effective disease management. Field experiments were conducted in two paddy fields at Wuyuan County in 2016 and 2017 to determine the effects of head covering and its timing on the infection of rice panicle blast. Results revealed that panicle blast was reduced significantly by covering rice heads with sulfuric acid paper bags, regardless of the covering time, ranging from initial heading to 15 days afterward, suggesting that rice panicles could be infected by blast pathogen even 15 days after initial heading. Panicle blast incidence was also found to be significantly influenced by plant dates, with higher panicle blast incidence observed in plots planted on early dates, suggesting adjusting plant dates could help rice panicles escape the infection by blast pathogen. The results from this study also highlighted the importance of cultivars and environmental conditions to panicle blast. In conclusion, besides planting blast-resistant cultivars, it is important to protect rice heads from the initial heading to the early dough stages, and fungicides should be applied according to infection warnings based on host, inoculum, and weather conditions., Competing Interests: The author(s) declare no conflict of interest.

Rice blast, caused by Magnaporthe oryzae , is the most destructive rice disease worldwide. The disease symptoms are usually expressed on the leaf and panicle. The leaf disease intensity in controlled environmental conditions is frequently quantified using a 0 to 5 scale, where 0 represents the absence of symptoms, and 5 represents large eyespot lesions. However, this scale restricts the qualitative classification of the varieties into intermediate resistant and susceptible categories. Here, we develop a 0 to 6 scale for blast disease that allows proper assignment of rice breeding lines and varieties into six resistance levels (highly resistant, resistant, moderately resistant, moderately susceptible, susceptible, and highly susceptible). We evaluated 40 common rice varieties against four major blast races (IB1, IB17, IB49, and IE1-K). Varieties carrying the Pi-ta gene were either highly resistant, resistant, or moderately resistant to IB17. The IE1-K race was able to break Pi-ta -mediated resistance of the rice varieties. The Pi-z gene conferred resistance to the IB17 and IE1-K races. The varieties M201, Cheniere, and Frontier were highly susceptible (score 6; 100% disease) to the race IE1-K. Moreover, varieties that were resistant or susceptible to all four blast races also showed similar levels of resistance/susceptibility to blast disease in the field. Taken together, our data proved that the 0 to 6 blast scale can efficiently determine the resistance levels of rice varieties against major blast races. This robust method will assist rice breeding programs to incorporate durable resistance against major and emerging blast races.[Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license., Competing Interests: The author(s) declare no conflict of interest.

Anthracnose caused by Elsinöe ampelina is an economically important disease that affects certain hardy and semihardy grapevine cultivars. The control of this disease requires repeated application of fungicides, which has financial and environmental consequences. In this study, leaf removal in the cluster area was studied with a view to facilitating integrated anthracnose management. First, the effect of leaf removal timing (BBCH stage 53 or 71) and intensity (one or both sides of rows) on the progression of anthracnose and on the microclimate was studied in plots planted with Vidal blanc ( Vitis vinifera ) at two sites in both 2020 and 2021. Overall, at both sites and in both years, anthracnose on leaves was more severe in plots without cluster zone leaf removal. Regardless of the timing of leaf removal, anthracnose severity on leaves and incidence of infected berries at harvest were significantly lower in plots where leaves had been removed on both sides of the rows compared with plots where leaves were removed on one side only. Second, anthracnose management programs with leaf removal, with or without disease risk estimation, were evaluated. All anthracnose management programs including leaf removal in the cluster zone reduced anthracnose development compared with the standard program without leaf removal. Overall mean leaf anthracnose severity, severity at harvest, and anthracnose incidence on clusters at harvest were lower in plots with leaf removal than in the standard program, but the differences between the two treatments were not significant ( P > 0.05). More fungicide applications were made in plots managed using the standard programs, specifically 13 applications, compared with plots managed based on assessing the weather-related risk of anthracnose, with 9 and 10 applications made at sites 1 and 2 for the risk-based program, respectively, and 5 and 7 applications made at sites 1 and 2, respectively, when microclimate within the cluster zone was considered. The results of this study clearly show the important role that leaf removal can play in managing grape anthracnose., Competing Interests: The author(s) declare no conflict of interest.

Powdery mildews are highly destructive fungal plant pathogens that have a significant economic impact on both agricultural and ecological systems worldwide. The intricate relationship between powdery mildews and their host plants has led to cospeciation. In this study, we conducted an extensive evaluation of powdery mildew hosts to provide an updated understanding of the host ranges and distributions of these fungi. The "United States National Fungus Collections Fungus-Host Dataset" is the primary source of information for our analyses. The analysis of the dataset demonstrated the worldwide prevalence of powdery mildews; the data contained over 72,000 reports of powdery mildews, representing ∼8.7% of all host-fungal records. We have updated the taxonomy and nomenclature of powdery mildews. In total, powdery mildews infect ∼10,125 host taxa belonging to 205 families of flowering plants, which accounts for 1,970 genera in 200 countries across six continents. Furthermore, we estimate that powdery mildews infect approximately 2.9% of described angiosperm species. Our study underscores the need for regular updates on powdery mildew host information due to the continuously evolving taxonomy and the discovery of new host taxa. Since 1986, we estimate an additional 1,866 host taxa, 353 genera, and 36 families have been reported. Additionally, the identification of powdery mildew hosts provides valuable insights into the coevolutionary dynamics between the fungi and their plant hosts. Overall, this updated list provides valuable insights into the taxonomy and geographic distribution of powdery mildew species, which builds upon the previous work of Amano in 1986. Discerning the geographic spread and host range of economically significant plant pathogens is vital for biosecurity measures and identifying the origins and expansion of potentially harmful pathogens., Competing Interests: The author(s) declare no conflict of interest.

Grape white rot can cause considerable yield losses in viticulture areas worldwide and is principally caused by Coniella diplodiella . The fungus overwinters in berry mummies on the soil surface or on the trellis and produces pycnidia and conidia that serve as primary inoculum. However, little is known about the temporal dynamics and dispersal pattern of C. diplodiella conidia. In this study, we investigated the production and dispersal of C. diplodiella conidia from a primary inoculum source, namely, affected mummified berries that overwintered in two vineyards in northern Italy in 2021 and 2022. Conidia of C. diplodiella were repeatedly produced in berry mummies from the budburst of vines to harvesting, with approximately 50 and 75% of the total conidia in a season being produced before fruit set and véraison, respectively. The production dynamics of C. diplodiella conidia over time were described by a Weibull equation in which the thermal time is the independent variable, with a concordance correlation coefficient of ≥0.964. A rainfall cutoff of ≥0.2 mm provided an overall accuracy of ≥0.86 in predicting conidial dispersal through rain splashes from berry mummies on the soil surface, with the number of dispersed conidia increasing with the amount of rainfall. The dispersal of conidia from mummies on the trellis by washing with rain required at least 6.1 mm of rain. The proposed mathematical equations and rain cutoffs can be used to predict periods with a high dispersal risk of C. diplodiella ., Competing Interests: The author(s) declare no conflict of interest.

English walnut ( Juglans regia L.) is an economically important hardwood tree species cultivated worldwide. Walnut heart rot disease leading to heartwood decay of trees has been frequently observed in a number of plantations in China. To identify the causal agent, 29 diseased stem samples were collected from walnut plantations in Beijing, and 54 fungal isolates were obtained. Koch's postulates were developed, and the results showed that Nothophoma juglandis , a species new to science, was the causal agent of walnut heart rot disease. Granulobasidium vellereum , a notable biocontrol agent, was coisolated with N. juglandis . An antagonistic assay on dual culture and walnut stems (both in the field and detached branches) proved that G. vellereum acted as a potential biocontrol agent against N. juglandis , as it could significantly inhibit the expansion of N. juglandis . The optimal temperature for mycelial growth and pathogenicity of N. juglandis was 26.6 and 27.0°C, respectively, which frequently occur in the summer of the walnut-growing regions in China., Competing Interests: The author(s) declare no conflict of interest.

Coniella granati , the causal agent of pomegranate crown rot, twig blight, and fruit decay, is an emerging worldwide pathogen with a heavy impact on pomegranate cultivation. In this study, we report the rapid spread of the fungus in Italian pomegranate orchards associated with crown rot symptoms and provide new results on fungal development, baseline sensitivity to different fungicides, and intraspecific variability by analyzing 11 isolates, representative of populations of the pathogen from comparable pomegranate orchards in different regions of Italy. In vitro assays showed that 25 to 30°C was the optimal range for both colony growth and conidial germination, corroborating the results previously obtained for Californian and Greek isolates. According to the baseline sensitivity assay on the response of colony growth and conidial germination to 10 fungicides, fludioxonil, thiophanate-methyl, tebuconazole, and cyprodinil were the most effective. Random amplified polymorphic DNA (RAPD) analysis, carried out using fourteen 10-mer primers, showed very low intraspecific variability (similarity coefficient >0.95), probably as a result of the recent spread of the pathogen in Italy and the uncommon occurrence of the sexual process as a source of genetic variability. In summary, this study provides new knowledge on C. granati that will be helpful for improving pomegranate crown rot management., Competing Interests: The author(s) declare no conflict of interest.

The effects of crop rotation and winter cover crops on soybean yield and colony-forming (CFU) units of Macrophomina phaseolina , the causal agent of charcoal rot (CR), are poorly understood. A field trial was conducted from 2011 to 2015 to evaluate (i) the impact of crop rotation consisting of soybean ( Glycine max [L.] Merr.) following cotton ( Gossypium hirsutum L.), soybean following corn ( Zea mays L.), and soybean following soybean over a 2-year rotation and its interaction with cover crop and (ii) the impact of different cover crops on a continuous soybean crop over a 5-year period. This trial was conducted in a field with 10 subsequent years of cover crop and rotation treatments. Cover crops consisted of winter wheat ( Triticum aestivum L.) and Austrian winter pea ( Pisum sativum L. subsp. sativum var. arvense ), hairy vetch ( Vicia villosa Roth), and a fallow treatment was evaluated with and without poultry litter application (bio-cover). Tissue CFU of M. phaseolina varied significantly between crop rotation treatments: plots where soybean was grown following cotton had significantly greater tissue CFU than plots following soybean. Poultry litter and hairy vetch cover cropping caused increased tissue CFU, though this effect differed by year and crop rotation treatment. Soil CFU in 2015 was substantially lower compared with 2011. However, under some crop rotation sequences, plots in the fallow treatment had significantly greater soil CFU than plots where hairy vetch and wheat was grown as a cover crop. Yield was greater in 2015 compared with 2011. There was a significant interaction of the previous crop in the rotation with year, and greater yield was observed in plots planted following cotton in the rotation in 2015 but not in 2011. The result from the continuous soybean planted over 5 years showed that there were no significant overall effects of any of the cover crop treatments nor was there interaction between cover crop treatment and year on yield. The lack of significant interaction between crop rotation and cover crop and the absence of significant differences between cover crop treatments in continuous soybean planting suggest that cover crop recommendations for midsouthern soybean growers may need to be independent of crop rotation and be based on long-term crop needs., Competing Interests: The author(s) declare no conflict of interest.

Black rot is a common disease of Gastrodia elata , causing serious threats to G. elata production. In this study, a total of 17 Cylindrocarpon -like strains were isolated from G. elata black rot tissues. Multilocus sequence analyses based on ITS, HIS, TEF, and TUB combined with morphological characterizations were performed to identify six Ilyonectria species, including four new species, Ilyonectria longispora , I. sinensis , I. xiaocaobaensis , and I. yunnanensis , and two known species, I. changbaiensis and I. robusta. The pathogenicity of 11 isolates comprising type strains of the four new species and representative isolates from each of the six species was tested on healthy tissues of G. elata . All isolates were pathogenic to G. elata tissues, and symptoms were identical to black rot disease, confirming that our isolates were the causal agents of black rot disease of G. elata ., Competing Interests: The author(s) declare no conflict of interest.

White rot, caused by Sclerotium cepivorum , is a serious disease that causes significant yield losses in Allium production. The pathogen persists in soil as sclerotia, which germinate in response to sulfur compounds in Allium root exudates. This study was aimed at investigating the potential of early-terminated Allium bait crops to reduce densities of S. cepivorum sclerotia in soil. In growth chamber experiments with white onion ( A. cepa cultivar 'Southport White Globe'), red onion ( A. cepa cultivar 'Marenge'), sweet onion ( A. cepa cultivar 'Walla Walla'), and bunching onion ( A. fistulosum cultivar 'Parade'), termination of all four Alliums at the first- and second-leaf stages reduced soil sclerotia populations by up to 62 and 76%, respectively. Examination of soil samples collected 4 weeks after crop termination indicated that sclerotia populations in bait crop treatments remained low when seedlings were terminated at the first- and second-leaf stages. In contrast, crop termination at the third-leaf stage resulted in an increase in sclerotia counts due to the pathogen reproduction on the bait crops. The reduction in sclerotia populations in soil due to early crop termination was also observed in replicated field trials. Greater reductions in sclerotia counts were observed when plants in these experiments were terminated chemically as opposed to mechanically. In-furrow fungicides did not reduce sclerotia numbers under the conditions tested. This study demonstrates the potential for early termination of Allium bait crops to help reduce white rot inoculum in soil., Competing Interests: The author(s) declare no conflict of interest.

Cercospora leaf blight (CLB) of soybean, caused by Cercospora cf. flagellaris , C. kikuchii , and C. cf. sigesbeckiae , is an economically important disease in the southern United States. Cultivar resistance to CLB is inconsistent; therefore, fungicides in the quinone outside inhibitor (QoI) class have been relied on to manage the disease. Approximately 620 isolates from plants exhibiting CLB were collected between 2018 and 2021 from 19 locations in eight southern states. A novel polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay based on two genes, calmodulin and histone h3 , was developed to differentiate between the dominant species of Cercospora , C. cf. flagellaris , and C. cf. sigesbeckiae . A multilocus phylogenetic analysis of actin, calmodulin, histone h3, ITS rDNA, and transcription elongation factor 1-α was used to confirm PCR-RFLP results and identify remaining isolates. Approximately 80% of the isolates collected were identified as C. cf. flagellaris , while 15% classified as C. cf. sigesbeckiae , 2% as C. kikuchii , and 3% as previously unreported Cercospora species associated with CLB in the United States. PCR-RFLP of cytochrome b ( cytb ) identified QoI-resistance conferred by the G143A substitution. Approximately 64 to 83% of isolates were determined to be QoI-resistant, and all contained the G143A substitution. Results of discriminatory dose assays using azoxystrobin (1 ppm) were 100% consistent with PCR-RFLP results. To our knowledge, this constitutes the first report of QoI resistance in CLB pathogen populations from Alabama, Arkansas, Kentucky, Mississippi, Missouri, Tennessee, and Texas. In areas where high frequencies of resistance have been identified, QoI fungicides should be avoided, and fungicide products with alternative modes-of-action should be utilized in the absence of CLB-resistant soybean cultivars., Competing Interests: The author(s) declare no conflict of interest.

The drought-resilient crop sorghum ( Sorghum bicolor [L.] Moench) is grown worldwide for multiple uses, including forage or potential lignocellulosic bioenergy feedstock. A major impediment to biomass yield and quality are the pathogens Fusarium thapsinum and Macrophomina phaseolina , which cause Fusarium stalk rot and charcoal rot, respectively. These fungi are more virulent with abiotic stresses such as drought. Monolignol biosynthesis plays a critical role in plant defense. The genes Brown midrib ( Bmr ) 6 , Bmr12 , and Bmr2 encode the monolignol biosynthesis enzymes cinnamyl alcohol dehydrogenase, caffeic acid O -methyltransferase, and 4-coumarate:CoA ligase, respectively. Plant stalks from lines overexpressing these genes and containing bmr mutations were screened for pathogen responses with controlled adequate or deficit watering. Additionally, near-isogenic bmr12 and wild-type lines in five backgrounds were screened for response to F. thapsinum with adequate and deficit watering. All mutant and overexpression lines were no more susceptible than corresponding wild-type under both watering conditions. The bmr2 and bmr12 lines, near-isogenic to wild-type, had significantly shorter mean lesion lengths (were more resistant) than RTx430 wild-type when inoculated with F. thapsinum under water deficit. Additionally, bmr2 plants grown under water deficit had significantly smaller mean lesions when inoculated with M. phaseolina than under adequate-water conditions. When well-watered, bmr12 in cultivar Wheatland and one of two Bmr2 overexpression lines in RTx430 had shorter mean lesion lengths than corresponding wild-type lines. This research demonstrates that modifying monolignol biosynthesis for increased usability may not impair plant defenses but can even enhance resistance to stalk pathogens under drought conditions., Competing Interests: The author(s) declare no conflict of interest.

Dollar spot (DS), caused by Clarireedia spp. (formerly Sclerotinia homoeocarpa ), is one of the most important diseases of turfgrasses worldwide. Benzovindiflupyr, a pyrazole carboxamide fungicide belonging to succinate dehydrogenase inhibitors, was recently registered for DS control. In this study, baseline sensitivity, toxicity, and control efficacy of benzovindiflupyr against Clarireedia spp. were evaluated. The frequency of sensitivities had a unimodal distribution (Kolmogorov-Smirnov, P > 0.10). The mean EC 50 value was 1.109 ± 0.555 μg/ml, with individual values ranging from 0.160 to 2.548 μg/ml. Benzovindiflupyr increased the number of hyphal offshoots and cell membrane permeability and inhibited oxalic acid production. Positive cross-resistance was observed between benzovindiflupyr and boscalid, but not between benzovindiflupyr and thiophanate-methyl, propiconazole, or iprodione. Benzovindiflupyr showed high protective and curative control efficacies in vivo and in field applications. Both protective and curative control efficacies of benzovindiflupyr were significantly better than propiconazole, and equivalent to boscalid, over 2 years of field research. The results have important implications for managing DS and fungicide resistance problems in Clarireedia spp., Competing Interests: The author(s) declare no conflict of interest.

Vetiver grass ( Chrysopogon zizanioides ) has been widely used in recent years for ecological environment management, restoration of degraded ecosystems, and essential oil extraction. In 2019, a leaf streak disease of C. zizanioides was observed in Zhanjiang, Guangdong Province, China. The disease appeared as large streak lesions on the leaves, on which conidiomata were formed. A pathogenicity test with the fungus isolated from these lesions confirmed Koch's postulates and thus the fungus as the causal agent of this disease. A morphological resemblance of the pathogen to Stenocarpella was noted upon microscopic examination. Phylogenetic trees inferred from both individual and combined ITS, LSU, and tef1 sequences confirmed the pathogen as a species of the Diaporthaceae and revealed it to be closely related to Phaeocytostroma and Stenocarpella species. As morphological characters clearly placed the pathogen in the genus Stenocarpella , it was described as S. chrysopogonis ., Competing Interests: The author(s) declare no conflict of interest.

Lettuce ( Lactuca sativa L.) production is greatly threatened by Verticillium wilt, which is caused by three pathogenic races (races 1, 2, and 3) of the soilborne fungus Verticillium dahliae . Race 1 is predominant, and resistant varieties that provide full protection against it are commercially available. However, heavily relying on race 1-resistant cultivars could shift the population towards resistance-breaking isolates and impact the durability of plant resistance. This study determined the inheritance of partial resistance to isolate VdLs17 of V. dahliae within Lactuca spp. using 258 F 2:3 progeny generated from a cross between two partially resistant accessions, 11G99 ( L. serriola ) and PI 171674 ( L. sativa ). Eight experiments were performed under greenhouse and growth room conditions across 3 years using a randomized complete block design, and segregation analysis was conducted to determine the inheritance pattern. The results indicate that partial resistance to isolate VdLs17 of V. dahliae is conditioned by a two-major-gene genetic model with additive-dominance-epistatic effects. Transgressive segregants were infrequent but observed in both directions, indicating that favorable and adverse alleles are dispersed in both parents. Combining favorable alleles of these two partially resistant parents appears to be challenging because of epistatic effects and a significant role of environment in disease severity. The probability of capturing favorable additive genes could be maximized by generating and evaluating a large population and making selections at late generations. This study provides valuable insights into the inheritance pattern of partial resistance to isolate VdLs17 of V. dahliae that will be helpful in designing efficient breeding strategies in lettuce.[Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license., Competing Interests: The author(s) declare no conflict of interest.

Wheat brown foot rot (WBFR), caused by a variety of phytopathogenic fungi, is an important soilborne and seedborne disease of wheat. WBFR causes wheat lodging and seedling dieback, which seriously affect the yield and quality of wheat. In this study, 64 isolates of WBFR were isolated from different wheat fields in Yancheng city, Jiangsu Province, China. The internal transcribed spacer, elongation factor 1α, and RNA polymerase II subunit were amplified and the sequencing results of the fragments were analyzed with BLAST in NCBI. Through morphological and molecular identification, all of the isolates were identified as Microdochium majus . Verification by Koch's postulates confirmed that M. majus was the pathogen causing WBFR. The antifungal activities of fludioxonil and prochloraz against 64 isolates of M. majus were determined based on mycelial growth inhibition method. The results showed that fludioxonil and prochloraz had good antifungal activity against M. majus. The mean 50% effective concentration values of fludioxonil and prochloraz against M. majus were 0.2956 ± 0.1285 μg/ml and 0.0422 ± 0.0157 μg/ml, respectively. Control efficacy for seed-coating treatments conducted in a greenhouse indicated that M. majus severely damaged the normal growth of wheat, while seed coating with fludioxonil or prochloraz significantly reduced the disease incidence and improved the seedling survival rates. At fludioxonil doses of 7.5 g per 100 kg and prochloraz doses of 15 g per 100 kg, the incidence was reduced by 22.26 and 25.33%, seedling survival rates increased by 25.37 and 22.66%, and control efficacy reached 70.02 and 72.30%, respectively. These findings provide vital information for the accurate diagnosis and effective management of WBFR., Competing Interests: The author(s) declare no conflict of interest.

Field experiments were conducted during the fall-winter seasons of 2017 to 2018 and 2018 to 2019 to evaluate the efficacy of various fungicides to control Neofabraea leaf lesion of olive. Field trials were conducted in the highly susceptible cultivar Arbosana in a commercial, super-high-density orchard in San Joaquin County, California. Up to eight fungicidal products were applied using an air blast backpack sprayer, and their efficacy was compared with different application strategies. Results showed that most products were effective in reducing infection by the pathogens and limiting disease severity. Overall, best disease control was achieved by thiophanate-methyl, cyprodinil, difenoconazole + cyprodinil, and chlorothalonil, providing up to 75% reduction in disease severity. Copper hydroxide did not control the disease. In 2018 to 2019, the fungicides difenoconazole + cyprodinil and ziram were evaluated in additional field trials using different application strategies (single, dual, and combined applications) suitable for pathogen resistance management. Results showed that both products provided significant reduction in disease severity (∼50%), although no differences in efficacy were found between the two products nor between the different application strategies. Both products performed equally using one or two applications at 2-week intervals following harvest., Competing Interests: The author(s) declare no conflict of interest.

Among the most damaging diseases of rubber trees is anthracnose caused by the genus Colletotrichum , which leads to significant economic losses. Nonetheless, the specific Colletotrichum spp. that infect rubber trees in Yunnan Province, an important natural rubber base in China, have not been extensively investigated. Here, we isolated 118 Colletotrichum strains from rubber tree leaves exhibiting anthracnose symptoms in multiple plantations in Yunnan. Based on comparisons of their phenotypic characteristics and internal transcribed spacer ribosomal DNA sequences, 80 representative strains were chosen for additional phylogenetic analysis based on eight loci ( act , ApMat , cal, CHS-1 , GAPDH , GS , his3 , and tub2 ), and nine species were identified. Colletotrichum fructicola , C. siamense , and C. wanningense were found to be the dominant pathogens causing rubber tree anthracnose in Yunnan. C. karstii was common, whereas C. bannaense , C. brevisporum , C. jinpingense , C. mengdingense , and C. plurivorum were rare. Among these nine species, C. brevisporum and C. plurivorum are reported for the first time in China, and two species are new to the world: C. mengdingense sp. nov. in the C. acutatum species complex and C. jinpingense sp. nov. in the C. gloeosporioides species complex. Their pathogenicity was confirmed with Koch's postulates by inoculating each species in vivo on rubber tree leaves. This study clarifies the geographic distribution of Colletotrichum spp. associated with anthracnose on rubber trees in representative locations of Yunnan, which is crucial for the implementation of quarantine measures., Competing Interests: The author(s) declare no conflict of interest.

Sclerotinia stem rot (SSR) is a major disease of soybean across the Upper Midwest region of the United States. Management of this disease has relied on fungicide applications, but due to the environmental conditions necessary for SSR to develop, many of these applications are unnecessary. To mitigate this, predictive models have been developed using localized weather data for predicting the formation of Sclerotinia sclerotiorum apothecia, the inoculum source of SSR, and these models were integrated into a decision support system called Sporecaster. However, these models do not account for the soybean resistance levels to SSR. In this study, fungicide trials were performed across seven site-years in Wisconsin between 2020 and 2022 examining fungicide applications applied at one of three action thresholds (low, moderate, and high) following Sporecaster recommendations in combination with four soybean varieties representing three SSR resistance levels (susceptible, moderately resistant, and resistant). From these trials, the low and moderate action thresholds resulted in similarly low disease severity index (DIX) levels comparable to the standard across all varieties. However, the low action threshold was most accurate for predicting SSR development in the susceptible variety, and the high action threshold was most accurate for predicting SSR development for the three resistant varieties. Both the susceptible soybean and a moderately resistant line yielded similarly high results. Additionally, the use of all fungicide applications led to similar partial profits at grain sale prices of either $0.44 or $0.55 kg -1 . Overall, this study uncovered relationships between soybean resistance levels to SSR and Sporecaster, allowing for improved recommendations for fungicide applications., Competing Interests: The author(s) declare no conflict of interest.