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Plant Disease

@plantdiseasej.bsky.social

The leading international journal for rapid reporting of research on new, emerging, and established plant diseases. Published by The American Phytopathological Society.

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Plant Disease @plantdiseasej.bsky.social · 12h ago

By reconstructing the genetic evolution of the South African #Puccinia graminis f. sp. tritici population, Botma Visser et al. identified four genetic lineages over the last 116 years, all the result of exotic introductions into the country. Learn more: https://doi.org/10.1094/PDIS-06-25-1302-RE

Fig. 1. Genetic comparison of 11 herbarium Puccinia graminis specimens with 19 South African and international control P. graminis f. sp. tritici race isolates using an unrooted neighbor-joining phylogram prepared in DARwin 5.0.158 (Perrier and Jacquemoud-Collet 2006). Allelic data generated using seven microsatellite markers (Karaoglu et al. 2013) were used. The herbarium specimens are indicated in bold, the international control race isolates are underlined, and the South African control race isolates are given in normal text. The year of first collection is given in brackets, while bootstrap values above 80% are indicated above the connecting branches.

Plant Disease @plantdiseasej.bsky.social · 2d ago

Findings from Zakaria Janfi et al. suggest #Aspergillus minisclerotigenes presents a significant emerging threat to food safety in Mediterranean pistachio production, combining robust ecological adaptations with unprecedented toxigenic potential: https://doi.org/10.1094/PDIS-08-25-1744-RE

Fig. 1. Phylogenetic analysis of Aspergillus spp. section Flavi based on β-tubulin and calmodulin gene sequences. A, β-tubulin gene tree.

Plant Disease @plantdiseasej.bsky.social · 3d ago

#Ganoderma species have been associated with wood decay of dead or dying trees. Daisy H. Ahumada and David M. Rizzo tested the pathogenicity of Ganoderma species in California agricultural and native hosts: https://doi.org/10.1094/PDIS-05-25-1082-RE

Fig. 1. Longitudinal cross section through inoculation site, showing discolored wood and decay on a sample from peach rootstock ‘Nemaguard’ inoculated with Ganoderma adspersum.

Plant Disease @plantdiseasej.bsky.social · 4d ago

Hengming Luo et al. provide the first report on the distribution and variation of AVR-Pita3 in #Magnaporthe oryzae populations across rice-growing regions in Southwest China: https://doi.org/10.1094/PDIS-09-25-1912-RE #plantdisease

Fig. 2. Neighbor-joining phylogenetic tree of AVR-Pita3 among 188 isolates of Magnaporthe oryzae collected across rice-growing regions in Southwest China. AVR-Pita3 variants clustered into two distinct groups: cluster A comprises the haplotype H1 from Eleusine indica (same with GenBank accession DQ855958.1 from E. coracana), while cluster B contains the isolates of the haplotypes H2 to H5 from the Oryza sativa host. The haplotype H2 is the original haplotype of H3 to H5 in evolutionary courses.

Plant Disease @plantdiseasej.bsky.social · 5d ago

To evaluate the effectiveness of soybean leaf-associated gemygorvirus 1 against #Sclerotinia sclerotiorum, Shin-Yi Marzano et al. tested three formulations in greenhouse and field settings: https://doi.org/10.1094/PDIS-06-25-1215-RE #plantdisease

Fig. 2. In the greenhouse, tomato plants sprayed with fungal homogenate at optical density (OD600) 4.0 and 3.0 were visibly healthier than the heat-inactivated (HI) homogenate-sprayed controls. Both sprays showed a reduction in white mold symptoms when challenged with virulent Sclerotinia sclerotiorum, resulting in an improved yield. The average amount of sclerotia produced per plant at harvest was greatly reduced by fungal homogenate sprays at either OD of 3.0 or 4.0 (right). PF, particle filtrate.

Plant Disease @plantdiseasej.bsky.social · 6d ago

Takehiro Ohki and Hidekazu Maejima identified wheat cultivars that exhibited resistance to Japanese soil-borne wheat mosaic virus, which was confirmed through foliar inoculation. This is the first known report of such resistance in furoviruses: https://doi.org/10.1094/PDIS-07-25-1385-RE

Fig. 1. Infection with in vitro transcripts derived from infectious clones in wheat. A, Symptoms on upper leaves of Nourin 61 at 4 weeks after inoculation with JSB-Yw and CW-Mr. B, Western blot analysis of leaves infected with JSB-Yw and CW-Mr. M, Precision Plus Protein Prestained Standard (Bio-Rad Laboratories, Hercules, CA, U.S.A.); lane 1, JSBWMV Yw isolate; lane 2, JSB-Yw; lane 3, CWMV Mr isolate; lane 4, CW-Mr; H, healthy leaf. JSB-Yw, the virus obtained from pJSB-Yw RNA1 and RNA2; CW-Mr, the virus obtained from pCW-Mr RNA1 and RNA2; JSBWMV, Japanese soil-borne wheat mosaic virus; CWMV, Chinese wheat mosaic virus.

Plant Disease @plantdiseasej.bsky.social · 6d ago

Longfei Wu et al. identified QTL associated with partial resistance to #Aphanomyces euteiches and Fusarium avenaceum in field pea and developed a consensus map of QTL controlling resistance to Aphanomyces and Fusarium root rots: https://doi.org/10.1094/PDIS-06-25-1147-RE #plantdisease

Fig. 1. Correlation analysis among best linear unbiased predictors (BLUPs) for disease severity (d), vigor (v), and plant height (h) in A, the RIL-1 population inoculated with Aphanomyces euteiches (AE), Fusarium avenaceum (FA), or Fusarium graminearum (FG), and B, the RIL-2 population inoculated with AE and FA. Note: r values > 0.3 are significant at P < 0.05.

Plant Disease @plantdiseasej.bsky.social · last wk.

Begoña I. Antón-Domínguez et al. evaluated carob and pomegranate extracts as inducers of resistance against #Verticillium wilt in olive tree. Learn more: https://doi.org/10.1094/PDIS-05-25-1032-RE #plantdisease

Fig. 1. Relative expression of marker genes related to A, salicylic acid carboxyl methyltransferase (OeSAMT); B, TIFY transcription factor (OeTIFY); C, 9-cis-epoxy carotenoid dioxygenase (OeNCED); and D and E, polyphenol oxidases (OePPO1 and OePPO2) in stem and root samples from olive plants of cultivar Picual that were noninoculated and treated with pomegranate or carob extracts. The expression of each gene at each sampling time was relative to the first value on each graph (value = 1.0). For each graph, columns represent the mean of three replicated plants, and vertical bars the standard error of the means. For each graph, columns with different letters differ significantly according to Fisher’s protected LSD test at P = 0.05.

Plant Disease @plantdiseasej.bsky.social · last wk.

Arne Stensvand, Håvard Eikemo, and Anne-Grete Roer Hjelkrem studied disease symptoms, sources of inoculum, and patterns of spore release of #Mycosphaerella ribis over 3 years in an organic blackcurrant planting receiving no fungicide applications: https://doi.org/10.1094/PDIS-08-25-1675-RE

Fig. 1. Mycosphaerella leaf spot caused by Mycosphaerella ribis in blackcurrants

Plant Disease @plantdiseasej.bsky.social · last wk.

Utsala Shrestha et al. evaluated wheat cover crop residue as an anaerobic soil disinfestation amendment at 3 growth stages with varying lignin-to-nitrogen ratios on survival of Fusarium cugenangense, Globisporangium sylvaticum, and Rhizoctonia fragariae: https://doi.org/10.1094/PDIS-07-25-1425-RE

Fig. 1. Effect of 3-week anaerobic soil disinfestation (ASD) treatments with wheat crop residue (growth stages vegetative, reproductive, or mature), ASD with wheat bran, and nonamended (non-ASD) control on percentage of manganese oxide and iron oxyhydroxide paint solubilized during ASD. ASD amendments were applied at a rate of 4 mg carbon/g soil (approximately 9 g amendment/kg soil). Within mineral paint type, higher paint removal represents more anaerobic (reducing) conditions owing to reduction of Fe and Mn minerals to soluble forms. Data presented are combined results from Fusarium cugenangense and Globisporangium sylvaticum trials. Within mineral paint type, bars with the same letters are not significantly different at P < 0.05 according to Fisher’s protected least significant difference test. Error bars indicate standard error with 16 total replicates (4 biological replicates/trial × 2 trials × 2 studies; F. cugenangense and G. sylvaticum). L:N = lignin-to-nitrogen ratio.

Plant Disease @plantdiseasej.bsky.social · 2w ago

Most damage associated with fire blight is due to blossom blight, so less research has been dedicated to shoot infections. Ricardo Delgado Santander et al. evaluated the efficacy of chitosan, rhamnolipids, and caprylic acid against shoot trauma blight: https://doi.org/10.1094/PDIS-07-25-1382-RE

Fig. 1. Phytotoxicity of sodium caprylate on ‘Fuji’ apple seedlings 24 h postspray. Pictures show progressive reduction of necrotic lesion development as sodium caprylate concentrations decrease from 0.4 to 0%.

Plant Disease @plantdiseasej.bsky.social · 2w ago

Leaf spot disease was observed on Hemerocallis citrina plants in China. Xiaojing Shi et al. present the first study to identify and document #Boeremia shanxiensis as a novel fungal species and a new pathogen responsible for leaf spot disease on H. citrina: https://doi.org/10.1094/PDIS-09-25-1940-SC

Fig. 1. Symptoms, colony morphology, and microscopic characteristics of the Boeremia shanxiensis JZ-DT2 isolate. A, Leaf spot on a Hemerocallis citrina leaf in fields. B and C, Leaf spots on front and rear of a H. citrina leaf in the pathogenicity test. D and E, Front and rear of the colony on potato dextrose agar. F and G, Front and rear of the colony on oat agar. H and I, Front and rear of the colony on malt extract agar. J and K, Pycnidia. L, Conidia.

Plant Disease @plantdiseasej.bsky.social · 2w ago

Usha Bhatta and Shavannor M. Smith found that maize-teosinte near-isogenic lines and teosinte are valuable genetic resources for enhancing #Ustilago maydis—the causal pathogen of corn smut disease—resistance in cultivated maize: https://doi.org/10.1094/PDIS-05-25-1023-RE #plantdisease 🌽

Fig. 1. Ustilago maydis inoculation methods at different developmental stages. A, Seedling stage: needle inoculation with U. maydis suspension culture (1 × 106 cells/ml) into the seedling stem above the soil line at the three-leaf stage. B, Ear stage: silk channel inoculation 4 to 6 days after silk emergence (silks shown at typical 4 to 5 cm length when inoculated). C, Tassel stage: leaf whorl inoculation 3 to 10 days before tassel emergence from the uppermost leaf sheath (red arrow). White latex gloves indicate points of inoculation.

Plant Disease @plantdiseasej.bsky.social · 2w ago

Leandro J. S. Shibutani, Isabela V. Primiano, and Renato B. Bassanezi found that reducing spray intervals can limit ‘Candidatus Liberibacter asiaticus’ transmission during periods of shoot growth and continuous vector pressure: https://doi.org/10.1094/PDIS-08-25-1758-RE #plantdisease

Fig. 1. Schematic representation of experiments

Plant Disease @plantdiseasej.bsky.social · 2w ago

Suman Parajuli, Mary Ruth McDonald, and David Wolyn developed a detached spear screen for purple spot (#Stemphylium vesicarium) on asparagus spears that correlates with natural field infection: https://doi.org/10.1094/PDIS-01-25-0216-RE #plantdisease

Fig. 2. Spear purple spot severity among four asparagus cultivars under different sucrose treatments for two replicate experiments in each of 2021 (A and B) and 2022 (C and D). The lower portions of inoculated spears were incubated in 0, 5, or 10% sucrose solutions. Mean ± SE (n = 3). Means with the same letter are not significantly different according to Tukey’s honestly significant difference test (P ≤ 0.05), both within and among cultivars at each sampling date.

Plant Disease @plantdiseasej.bsky.social · 2w ago

Matthew West, Olive LoGrasso, and Robyn Roberts developed a colorimetric LAMP bioassay to detect wheat streak mosaic virus and/or Triticum mosaic virus, using either RNA or cDNA as the genomic template. Learn more: https://doi.org/10.1094/PDIS-09-25-1938-RE #plantdisease

Fig. 4. Loop-mediated isothermal amplification (LAMP) bioassay schematic.

Plant Disease @plantdiseasej.bsky.social · 2w ago

Studies from Chaydon O’Fallon, Helga Förster, and James E. Adaskaveg demonstrate that the new Oomycota fungicides oxathiapiprolin and fluopicolide can provide highly effective control of #Phytophthora crown and trunk cankers in young almond orchards: https://doi.org/10.1094/PDIS-08-25-1692-RE

Fig. 1. Field studies on the efficacy of soil fungicide applications in reducing the incidence of gumming crown and trunk cankers and tree death of Nonpareil almond grafted on Hansen 536 or Nemaguard rootstocks after soil inoculation with Phytophthora cactorum.

Plant Disease @plantdiseasej.bsky.social · 2w ago

A multiyear field study conducted by Johanna Wesche, Jeffrey A. Hopkins, and Guido Schnabel showed that biorational-DMI fungicide mixtures can provide blossom blight and brown rot of nectarine control comparable to full-rate synthetic fungicide programs: https://doi.org/10.1094/PDIS-07-25-1568-RE

Fig. 1. Postharvest brown rot incidence (percentage) of experimental treatments with focus on 1/3 Propi-Star EC in 2023 (A) and 2025 (B). Means ± SE of four trees per treatment with 56 fruit evaluated per tree. Different letters indicate significant differences between treatments; Tukey P > 0.05. Lowercase letters are for 3 days postharvest, and capital letters are for 7 days postharvest. 1/3 Propi-Star EC = one-third–label rate of Prop-Star EC.

Plant Disease @plantdiseasej.bsky.social · 2w ago

In 2023, an epidemic outbreak of stem rot disease was observed in commercial adzuki bean fields in China. Shuni Wang et al. identified two #Fusarium spp. as the causal agents, representing the first report of these fungi causing stem rot on adzuki bean: https://doi.org/10.1094/PDIS-07-25-1498-RE

Fig. 1. Symptoms and morphological characteristics of Fusarium graminearum and F. oxysporum causing adzuki bean stem rot. (A and E) Field symptoms of stem rot in adzuki bean; (B and F) symptoms in adzuki bean plants artificially inoculated with F. graminearum (B) and F. oxysporum (F); (C and G) colony morphology of F. graminearum (C) and F. oxysporum (G) on potato dextrose agar after 7 days; (D and H) conidial morphology of F. graminearum (D) and F. oxysporum (H).

Plant Disease @plantdiseasej.bsky.social · 2w ago

Results from Natacha Motisi et al. suggest that climate change may not simply amplify coffee leaf rust, caused by the obligate parasite #Hemileia vastatrix, risks but rather shift the window of infection opportunities. Learn more about their findings: https://doi.org/10.1094/PDIS-04-25-0845-RE

Fig. 2. Probability of germination of Hemileia vastatrix spore as predicted by the model in varying combinations of temperature (from 16° to 32°C) and atmospheric CO2 (from 181 to 700 ppm). Solid lines correspond to the mean probabilities, and areas between dashed lines show the 95% confidence interval for the mean.

Plant Disease @plantdiseasej.bsky.social · 2w ago

Gracia Montilla-Bascon et al. evaluated a Mediterranean oat collection comprising over 700 Avena sativa and A. byzantina accessions to identify durable sources of resistance against a highly virulent Mediterranean rust isolate: https://doi.org/10.1094/PDIS-06-25-1136-RE #Puccinia #plantdisease 🌾

Fig. 3. Light micrographs showing examples of Puccinia coronata f. sp. avenae development and leaf mesophyll cell responses of oat accessions, viewed by incident fluorescence microscopy.

Plant Disease @plantdiseasej.bsky.social · 3w ago

Pepper southern blight, caused by Agroathelia rolfsii, is a serious soilborne fungal disease. Tuhong Wang et al. identified a novel strain of Bacillus velezensis, SEC-482, with significant antagonistic effect against A. rolfsii: https://doi.org/10.1094/PDIS-09-25-1967-RE

Fig. 1. Potential of the strain SEC-482 as a biocontrol agent against Agroathelia rolfsii. A to D, Inhibition of A. rolfsii by the strain SEC-482. A, Inhibition rates were calculated after 3 days of growth; B, negative control (untreated); C, inhibition by SEC-482; D, inhibition by 240 mg/liter of thifluzamide. E to H, Phenotypic performance of pepper plants under different treatments. E, The control efficacy of different treatments against pepper southern blight in the greenhouse; F, pepper plants treated with CK1 (LB); G, pepper plants treated with fermentation broth of the strain SEC-482 (15 ml/pot); H, pepper plants treated with CK2 (240 mg/liter of thifluzamide). I, SEM image of A. rolfsii mycelia (control); J, SEM image of A. rolfsii mycelial inhibition by SEC-482.

Plant Disease @plantdiseasej.bsky.social · 3w ago

Kunlaya Prakobsub et al. establish a quantitative pathosystem for plantago asiatica mosaic virus in lilies and provide a basis for future research into the mechanism underlying symptom development and disease management strategies in commercial production: https://doi.org/10.1094/PDIS-03-25-0686-RE

Fig. 2. Correlation between disease severity and virus accumulation of all samples of KK-infected leaves (r = 0.67), the data points are categorized by each of the four experiments. Autumn 2024 (green), spring 2024 (pink), autumn 2023 (blue), and spring 2023 (yellow).

Plant Disease @plantdiseasej.bsky.social · 3w ago

"Evaluating Pistachio Rootstock Tolerance to Phytophthora Root and Crown Rot," by Alejandro I. Hernandez-Rosas et al. Learn more: https://doi.org/10.1094/PDIS-10-25-2051-RE #plantdisease #Phytophthora

Fig. 1. Trial 1. Average stem lesion length of pistachio rootstocks wound-inoculated with Phytophthora mediterranea, Phytophthora niederhauserii, and Phytophthora taxon walnut. Bars with different letters indicate significant differences among rootstock × Phytophthora spp. interaction based on Tukey’s honestly significant difference test (α = 0.05). Vertical lines on columns are the standard error of the mean. PGI = Pioneer Gold I; UCBI = University of California Berkeley I.

Plant Disease @plantdiseasej.bsky.social · 3w ago

Over 18,000 metric tons of blackberries are produced in the United States, predominantly in Oregon. Dan Fager et al. provide insights into the characterization of blackberry calico virus, a previously overlooked pathogen affecting Rubus spp. Learn more: https://doi.org/10.1094/PDIS-06-25-1232-RE

Fig. 1. Blackberry calico symptoms on A, blackberry cv. Marionberry in field conditions, B, blackberry cv. Black diamond in greenhouse conditions, C, grafted black raspberry cv. Munger, and D, grafted blackberry cv. Caddo.

Plant Disease @plantdiseasej.bsky.social · 3w ago

Greta Dardani et al. developed two cost-effective SYBR Green qPCR assays for the specific detection and quantification of #Botryosphaeria dothidea and species within the #Neofusicoccum parvum-ribis complex: https://doi.org/10.1094/PDIS-04-25-0888-SR

Fig. 1. Standard curve obtained with genomic DNA from A, Botryosphaeria dothidea and B, Neofusicoccum parvum. The curves illustrate the correlation between the 10-fold dilution of the target DNA amounts (ranging from 20 ng to 200 fg) and the quantification cycle (Cq) values. Error bars represent the standard deviations. Regression equations of standard curves are shown for each strain. Each reaction was repeated at least three times with three replicates for each point.

Plant Disease @plantdiseasej.bsky.social · 3w ago

Carmen Luque-Cruz et al. explored the interaction between #Botryosphaeria dothidea and #Neofusicoccum parvum causing cankers in almond and effect of wood age on infection: https://doi.org/10.1094/PDIS-08-25-1734-RE #plantdisease

Fig. 2. Cankers developed on green (A) and lignified shoots (B) of potted almond plants of cultivar Avijor grafted on GF-677 rootstock at 2 and 12 months after inoculation, respectively, with conidial suspensions of Botryosphaeria dothidea and Neofusicoccum parvum. The following treatments were performed: noninoculated controls, single inoculations of B. dothidea or N. parvum, simultaneous inoculation with both pathogens (Bd × Np); B. dothidea and N. parvum, or N. parvum and B. dothidea, with the second species inoculated at 4 days after the first one in each case (Bd × Np-4d and Np × Bd-4d, respectively).

Plant Disease @plantdiseasej.bsky.social · 3w ago

#Pseudomonas syringae pv. actinidiae (Psa) threatens kiwifruit production worldwide. Lan Peng et al. developed assays that enable accurate discrimination between viable and dead Psa cells: https://doi.org/10.1094/PDIS-04-25-0907-SR #plantdisease

Fig. 5. Detection of viable Pseudomonas syringae pv. actinidiae (Psa) cells in field-collected kiwifruit pollen using PMA-PCR (A) and PMA-LAMP (B). Lanes 1 to 28 represent individual pollen samples collected from a commercial kiwifruit orchard. PMA treatment was performed under optimized conditions: 130 μg/ml PMA, 5 min of dark incubation, and 20 min of light exposure to a 650-W halogen lamp. CK+, positive control, 50 ng/μl genomic DNA of Psa. NC, negative control, sterile water. PMA, propidium monoazide; LAMP, loop-mediated isothermal amplification; qPCR, quantitative polymerase chain reaction.

Plant Disease @plantdiseasej.bsky.social · 3w ago

Delong Kong et al. isolated and identified an endophytic fungus, Penicillium oxalicum G11, from healthy wheat plants and evaluated its antagonistic mechanisms and biocontrol potential against #Rhizoctonia cerealis, a causal pathogen of wheat sharp eyespot: https://doi.org/10.1094/PDIS-06-25-1284-RE

Fig. 6. Detection of G11 colonization in wheat roots.

Plant Disease @plantdiseasej.bsky.social · 3w ago

YOLO-APLD, developed by Xinlong Li et al., exhibits strong detection performance in apple leaf disease detection and can provide practical technical support for precision pesticide application in orchards and on-site disease monitoring. Learn more: https://doi.org/10.1094/PDIS-07-25-1440-RE

Fig. 9. Comparison of the YOLO series model’s visualization detection results.