Plant disease最新文献

{"title":"First report of Fruit rot caused by <i>Mucor inaequisporus</i> on Chinese plum (<i>Prunus salicina</i>) in China.","authors":"Chunqing Pan, Xinqi Mao, Yuanyi Zhang, Dong Liu, Yanju Zhang","doi":"10.1094/PDIS-08-24-1695-PDN","DOIUrl":"10.1094/PDIS-08-24-1695-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Plum (Prunus salicina Lindl.) is planted in many places in China. In July 2021, plums were found to be covered with unfamiliar yellow mycelia on the plum trees and on the ground in the campus of Northeast Agricultural University in Harbin. The symptoms on the fruit were initially manifested as white mycelium and water damage, then the mycelium turned yellow and the water immersion area expanded rapidly. Finally, the whole fruit is covered by yellow, dense mycelium, so that the flesh becomes soft rot, and fall off, causing about 3~5% economic loss (Fig. 1A, B). The thirty diseased fruits were collected, and the tissue (5 × 5 mm) was cut from the diseased fruits, and then surface sterilized with 75% alcohol for 30 s, soaked in 3% sodium hypochlorite for 5 min, washed with sterile distilled water for 3 times, and inoculated on potato dextrose agar (PDA) and malt extract agar (MEA) at 28 °C. Strains growing around the tissues from samples were subcultured on PDA, and 3 strains (DNMI01, DNMI02 and DNMI03) were obtained using the single-spore isolation method. On PDA, the hyphae were light yellow in the early stage, and became golden yellow in the later stage. The edge of the colony was fan-shaped, and the growth rate was extremely fast for 3 days to reach a full dish (Fig. 1G). On MEA, the mycelium was light yellow at the initial stage, and became grayish black in the later stage. The colony grew irregularly and grew slowly (Fig. 1H). Sporangiospores have two shapes, yellow, aseptate, globose or subglobose 7.7 to 14.1 × 8.5 to 13.9 μm (n=30), oval 2.5 to 6.4 × 6.2 to 12.0 μm (n=30, Fig. 1C). Columellae frequently pyriform, oval, colorless or yellowish, and 31.5 to 53.7 μm × 50.6 to 83.2 μm (n=30, Fig. 1D, E). Sporangia globose or subglobose, yellow, wall echinulate, and 55.3 to 109.1 × 67.9 to 123.5 μm (n=30, Fig. 1F) (Santiago et al. 2013). Acetyl trimethyl ammonium bromide method was used to extract DNA from 3-day-old. The internal transcribed spacer (ITS) and 28S rRNA partial gene sequences were amplified by primers ITS1 / ITS4 (White et al. 1990) and LR0R / LR5 (O'Donnell 1993), respectively. The sequences obtained by polymerase chain reaction (PCR) were sequenced and the sequences were deposited in GenBank with accession numbers ITS, OR136169-OR136171, and LSU, OR136179-OR136181. BLAST analysis of these sequences showed 96.13%-96.48% similarity to Mucor inaequisporus culture CBS255.36 (JN206177.1), 99.28%-99.58% to culture CBS255.36 (MH867301.1), respectively (Walther et al. 2013). Phylogenetic analysis by maximum likelihood method (MEGA7.0) generated based on the ITS, LSU sequences indicated that the strains formed a supported clade to the related M. inaequisporus type sequences. Strains was found to be most closely related to M. inaequisporus and far from other species. Based on morphological and phylogenetic characteristics, strains DNMI01 to DNMI03 was identified as M. inaequisporus (Lee et al. 2020; Ren et al. 2023). According to Koch ","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of Fungicides for the Management of Glomerella Leaf Spot and Bitter Rot on Apple in North Carolina.","authors":"Kendall Johnson, Rachel Kreis Douglas, W Chester Allen, Keith Yoder, Sherif M Sherif, Kerik Cox, Wayne Jurick, Aaron Weber, Sara M Villani","doi":"10.1094/PDIS-12-24-2773-RE","DOIUrl":"https://doi.org/10.1094/PDIS-12-24-2773-RE","url":null,"abstract":"<p><p>Glomerella leaf spot (GLS) and bitter rot caused by species in the <i>Colletotrichum gloeosporioides</i> species complex are the most economically devastating fungal diseases of apples in North Carolina. Crop losses have reached 100% in highly susceptible cultivars. In the southeastern United States, management of this disease has predominantly relied on broad-spectrum fungicide programs targeting several summer diseases of apples. To improve control of GLS and bitter rot, field experiments to evaluate the efficacy of multi- and single-site fungicides were conducted over multiple years in a 'Gala' research orchard located in Mills River, NC from 2017-2019. Fungicides representing different modes of action were applied in a non-rotational program from petal fall until the immediate pre-harvest period to assess their efficacy in reducing GLS incidence, shoot defoliation due to GLS, and pre-and post-harvest bitter rot. Of the fungicides evaluated, Captan 80WDG (a.i. captan), Merivon (a.i. fluxapyroxad and pyraclostrobin), Cabrio (a.i. pyraclostrobin), and Aprovia (a.i. benzovindiflupyr), provided good to excellent control against disease caused by Colletotrichum chrysophilum. In these programs, the incidence of GLS, expressed as relative area under the disease progress curve (rAUDPC), ranged from 4.6 to 43.8 in the Captan 80WDG (2019) and the Aprovia (2017) programs, respectively. The incidence of bitter rot at harvest in these programs from 2017-2019 ranged from 0.0% to 45.3% in the 2018 and 2017 Captan 80WDG programs, respectively. Conversely, the highest incidences of GLS and pre-harvest bitter rot were consistently observed in the Inspire (a.i. difenoconazole), Sercadis (a.i. fluxapyroxad) and untreated programs. Shoot defoliation due to GLS followed a similar trend across the evaluated fungicide programs. In addition to non-rotational fungicide programs, the effect of carrier water pH for applications of captan was evaluated for bitter rot control in Virginia and NC. No differences in captan efficacy were observed at either location. Results of this study will inform the development of new management programs for GLS and bitter rot in the southeastern United States and provide a foundation for the development of new season-long fungicide programs for apple disease management.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143449733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Occurrence of <i>Ophiopogon bodinieri</i> anthracnose caused by <i>Colletotrichum siamense</i> in China.","authors":"Airong Xie, Liudan Zeng, XiWen Xu, Jia Min Guo, Tao Li, HanQuan Chen, Run Hua Yi","doi":"10.1094/PDIS-12-24-2717-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-12-24-2717-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Ophiopogon bodinieri H.Lév. (Asparagaceae) is a perennial flowering herbaceous plant native to China, and widely cultivated as ornamental plant in South China. During May 2024, an anthracnose was observed on approximately 70% of O. bodinieri in a farm at Mazhang, Zhanjiang, Guangdong Province (22°6'14.7''N,110°27'26.8''E). The symptoms appeared first as small spots with irregular yellow or brown halos, subsequently, the lesions darkened and expanded, covering the leaves. Twenty four plants infected with the disease were sampled, and the pathogen was isolated from sixteen of the plants. Disease tissues (5×5mm) were surface disinfected with 75% ethanol and 3% hydrogen peroxide, rinsed with sterilized distilled water three times, and placed onto potato dextrose agar (PDA) medium containing 50 mg/L of penicillin. The plates were incubated in the dark at 28°C for 3 days. Isolates obtained by transferring the hyphal tips onto fresh PDA were further cultured by single spore dilution method (Choi et al. 1999). Colonies with dense, cottony aerial mycelia were initially white and became grey after 8 days. Conidia were hyaline, one-celled, guttulate, oblong with rounded ends, 13.2 to 17.9 µm × 3.8 to 5.7 µm (n=50). Appressoria formed from mycelia were dark brown, mostly irregular lobes and becoming complex with age, 12.9 to 15.6µm × 7.8 to 11.9 µm (n=50). Setae were absent. Morphological and cultural characteristics were identical to Colletotrichum siamense. To further identify, internal transcribed spacer (ITS) region, B-tubulin (tub), glyceraldehydes-3-phosphate dehydrogenase (gapdh), chitin synthase (chs), actin (act) and calmodulin (cal) genes of isolate YJ8-2 and YJ1-3 were amplified and sequenced with the primer pairs of ITS1/ITS4 (White et al. 1990), TUB-2Fd/4Rd, GAPDH-F/R, CHS-345R/79F, ACT-Rd/512F, CAL-CL1C/CL2C respectively (Weir et al. 2012). The sequences were submitted to GenBank (ITS: PQ327950 and PQ060497; TUB: PQ340881 and PQ061099; ACT: PQ340884 and PQ061095; GAPDH: PQ340882 and PQ061098; CHS: PQ340883 and PQ061097; CAL: PQ340885 and PQ061096). BLAST research showed the sequences of YJ8-2 and YJ1-3 had above 98% identity with C. siamense ex-type ICMP: 18578 (ITS: JX010171 (548/548 100%) and (545/546 99%); GAPDH:JX009924 (271/277 98%) and (260/266 98%); CAL:JX009714 (720/728 99%) and (726/731 99%); TUB: JX010404 (479/485 99%) and (466/467 99%); CHS:JX009865 (294/299 98%) and (254/256 99%); ACT:JX009518 (268/271 99%) and (270/271 99%)). A phylogenetic tree based on concatenated sequences of the six genes using maximum-likelihood method revealed that isolate YJ1-3 and YJ8-2 clustered in the same clade with C. siamense. To confirm pathogenicity, five healthy leaves of one-year-old O. bodinieri in the field were wiped with 75% ethanol and sterile water, wounded with a sterile needle. Three leaves were inoculated with 10 µl of spore suspension (1×105 conidia/ml), and two leaves were inoculated with sterile water as controls. The experiment ","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143449748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fungal and bacterial species associated with storage diseases in sugar beet from the Red River Valley of Minnesota and North Dakota.","authors":"Malick Bill, Shraddha Adhikari, Gillian O Bruni, Karen Klotz Fugate, Yunci Qi, Mohamed Fizal Khan, Zhaohui Liu, Shyam L Kandel","doi":"10.1094/PDIS-10-24-2188-RE","DOIUrl":"10.1094/PDIS-10-24-2188-RE","url":null,"abstract":"<p><p>Sugar beet is a major source of consumable sugar in domestic and industrial applications in the U.S. Sugar beet roots are stored for up to seven months under cold ambient temperature conditions in the Red River Valley (RRV) of Minnesota (MN) and North Dakota (ND). During this period, storage rots often develop that can reduce the sucrose content and processing quality of the roots. Knowledge of the pathogens responsible for this sucrose loss is limited but crucial for devising management strategies. This study was conducted to re-examine and identify storage pathogens infecting sugar beet roots in open non-ventilated piles in the RRV of MN and ND and characterize their prevalence and geographic distribution. In the first year of the study, over 50 roots exhibiting storage rot were collected from an outdoor non-ventilated pile (ONVP) in MN. In the successive year, 150 storage rot and damaged symptomatic roots were collected from five geographically distinct ONVPs with three located in MN and two located in ND. Penicillium spp., Geotrichum candidum, and Mucor spp., were common filamentous fungal species identified, while Pichia membranifaciens was the dominant yeast identified in both years of the study. Leuconostoc mesenteroides and G. cerinus were common bacterial isolates in both years of the study. Most of the bacterial isolates obtained from ONVP-4 (ND) (63%) and ONVP-5 (ND) (99%) during the second year of the study were identified as L. mesenteroides. This study identified fungal and bacterial species associated with storage diseases of sugar beet roots in the RRV of MN and ND, which is pivotal for implementing management strategies to minimize postharvest sucrose losses during sugar beet storage.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First Report of Purple Seed Stain Caused by <i>Cercospora cf. flagellaris</i> on Soybean in Korea.","authors":"Jung-Wook Yang, Yul-Ho Kim, In-Jeong Kang, Eun Young Kim, Yun-Hee Kim","doi":"10.1094/PDIS-12-24-2536-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-12-24-2536-PDN","url":null,"abstract":"<p><p>In November 2021 and 2022, soybean seeds exhibiting purple staining were collected from Suwon, Gimje, and Yeoncheon in Korea. The symptoms first appeared on aging leaves and eventually covered the entire leaf. Initial infection manifested as small yellow spots that turned light brown or white, accompanied by yellow halos, with visible clusters of conidia at the center. The seeds showed shallow purple discoloration on the seed coat and deep purple staining within the seed. Infected leaves were surface sterilized with 10% chlorine solution and cultured on general isolation media. Colonies appeared white to gray after incubation in a growth chamber at 25°C with a 12-hour photoperiod. Single-spore isolates were transferred to PDA with 6% sucrose, showing a color change to brown or dark shades. Three isolates were selected for identification and pathogenicity tests. Conidiophores were brown, straight or slightly curved, and uniformly wide, forming clusters of 5-12 on the leaf's lower surface, measuring 300-700 μm (average = 560 μm, n = 25). Conidia were hyaline, needle-shaped, straight or slightly curved, and tapered at the base, with 3-15 indistinct septa, measuring 60-240 μm (average = 180 μm, n = 25). DNA was extracted from the three isolates, and sequences of the internal transcribed spacer (ITS) regions 1 and 2, actin (ACT), HIS3, and calmodulin (CAL) were obtained. These sequences were deposited in GenBank (PQ578698, PQ583605, PQ583606, PQ583607 and PQ583608). BLAST search results revealed 99-100% identity with Cercospora flagellaris for ITS and ACT sequences. To fulfill Koch's postulates, the isolates were grown in a growth chamber (25°C, 12-hour photoperiod) for 20 days. Spore suspensions (10^4 spores/ml) with 0.01% Tween 20 were sprayed on Nuriol and Jangol cultivars. Inoculated plants were maintained in a humid environment for 72 hours and then transferred to a greenhouse. Control plants were sprayed with sterilized water and kept under the same conditions. Five weeks post-inoculation, all inoculated plants exhibited purple seed stain symptoms, while control plants remained healthy. The same pathogen was re-isolated from the inoculated plants. Cercospora flagellaris is known to affect a wide range of plant species in various countries, including the USA and Brazil. This is the first report of C. flagellaris causing purple seed stain on soybean in Korea. Soybean is a critical food and oil crop in Korea. Therefore, further studies are needed to assess the epidemiology, cultivar responses, fungicide sensitivity, and management strategies to support the sustainability and future potential of soybean cultivation in Korea.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143449747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Curvularia lingshanensis</i> sp. nov., a new pathogen causing stem and leaf rot on <i>Curcuma kwangsiensis</i> in China.","authors":"Jinbiao Liang, Hanyi Wang, Rongchang Wei, Chunshui Zhou, Jiali Su, Ze Liu, Siyu Lin, Jingyi Guo, Qi Gao, Hao Zhou","doi":"10.1094/PDIS-12-24-2685-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-12-24-2685-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Curcuma kwangsiensis S. G. Lee et C. F. Liang, a medicinal plant in the Zingiberaceae family, is cultivated in southwestern China (Feng et al., 2022). In May 2021 and 2022, a stem and leaf rot disease in C. kwangsiensi was observed in Qinzhou and Nanning, Guangxi Province, with an incidence of approximately 15% across the survey area (0.5 ha). Initial symptoms included brown, water-soaked lesions on tender leaves, which progressed to involve entire leaves and stems, ultimately causing the plant to turn yellow, soft, and slimy, leading to plant death. To identify the pathogen, 29 Curvularia-like strains were obtained from six symptomatic plants using tissue isolation methods and single-spore purification (Zhang et al., 2013). The fungus was consistently isolated from all six plants. Five isolates were selected for further investigation. On potato dextrose agar (PDA), colonies were sparse and grey. On oatmeal agar (OA), colonies were cottony, with a green fruiting zone and a pale grey aging zone. On malt extract agar (MEA), colonies exhibited irregular edges with a raised whitish zone. Conidia were induced on water agar (WA). Conidiophores were erect, short, septate, unbranched, and measured 11.5~35 × 2.7~4.9 μm (n = 50). Conidiogenous cells proliferated terminally, sympodially, were slightly verruculose to smooth-walled, light brown, and measured 3.2~12.0 × 2.5~5.3 μm (n = 40). Conidia were straight or clavate, seldom curved at the third cell from the base, mostly three-septate, and occasionally two-septate, olivaceous brown, and measured 11.0~27.9 × 4.5~11.0 μm (n = 70). The internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and elongation factor 1 alpha (EF-1α) loci were amplified using primers ITS1/ITS4 (White et al., 1990), GPD-1/GPD-2 (Berbee et al., 1999), and EF-983F/EF1-2128R (Carbone et al., 1999), respectively. The sequences were submitted to the GenBank. A phylogenetic analysis revealed that the five representative strains formed a distinct clade, separate from other known Curvularia species. They were closely related to C. radici-foliigena, C. radicicola, C. petersonii, and C. pseudoclavata (Marin-Felix et al., 2020; Raza et al., 2019; Tan et al., 2018), but differed in the characteristics of conidiophores, conidiogenous cells, and conidia. Based on morphology and multi-gene phylogeny, the pathogen was identified as C. lingshanensis sp. nov. To test pathogenicity, conidia from 2-week-old cultures of C. lingshanensis strain CK21.1 were resuspended to prepare conidial suspension (106 spores/mL). Six healthy 2-week-old C. kwangsiensi seedlings were used: three were sprayed with 2 mL conidial suspension, while the other three were treated with sterile water as controls. Inoculated plants were maintained in a greenhouse at 25°C with a 12-h photoperiod and approximately 90% humidity. Within 12 d, the C. kwangsiensi seedlings inoculated with CK21.1 conidia developed severe stem rot and water-soaked necr","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143414914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First Report of Powdery Mildew Caused by <i>Golovinomyces tabaci</i> on <i>Hibiscus trionum</i> L. in Xinjiang, China.","authors":"Shaohua Chen, Siyi Liu, Guiyuan Zhang, Chaoyang Ma, Zhiqiang Zhang, Fang Zhu, Hui Xi, Xuekun Zhang","doi":"10.1094/PDIS-11-24-2382-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-11-24-2382-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Hibiscus trionum L., a member of the Malvaceae family and Hibiscus genus, is a prevalent weed in agricultural fields across Xinjiang, China. In September 2023, powdery mildew was observed on H. trionum leaves in the cotton experimental field (0.133 ha) at Shihezi University, with the surfaces of the leaves covered with white powder. The mildly infected leaves displayed chlorosis, while those with severe infections exhibited senescence. In the field, we conducted a five-point sampling method across five 1 m² plots, examining a total of 100 weeds, of which 96% displayed these symptoms. Morphological analysis revealed conidiophores measuring 40.2-160.8 × 3.3-10 µm (without conidia), with a mean dimension of 80 × 9.2 µm, arising from the upper surface of hyphal mother cells or laterally, typically towards one end of the cell. Foot-cells were straight or curved, measuring 28.8-92.4 × 7.8-10.9 µm (mean 66 × 9.6 µm), followed by 2-4(-5) shorter cells, with the basal septum usually located at the junction with the supporting hypha. Conidia were transparent, cylindrical to nearly rectangular, with dimensions of 18.2-36.2 × 10.8-15.6 µm, consistent with the characteristics of Golovinomyces tabaci (Qiu et al., 2020). To confirm the morphological identification, the total genomic DNA of the representative strain GT-SHZ was extracted using the CTAB method (Doyle and Doyle. 1990). The ITS, 28S rDNA, and TUB2 sequences were amplified with the specific primers ITS5/ITS4(White et al., 1990), LSU1/LSU2 (Scholin et al., 1994), and TubF1/TubR1(Qiu et al., 2020), respectively. After TA cloning and sequencing, vector sequences were removed, and the sequences of the ITS, 28S rDNA, and TUB2 were deposited in GenBank under accession numbers PQ571799, PQ572139, and PQ586974, respectively. BLAST analysis indicated that the ITS, 28S rDNA, and TUB2 sequences of GT-SHZ were 100%, 98.58%, and 99.5% identical to ITS (MK937796.1), 28S rDNA (AB430816.1), and TUB2 (ON645928.1) of G. tabaci, respectively. A combined phylogenetic analysis of ITS, 28S rDNA, and TUB2 confirmed that the GT-SHZ clustered with G. tabaci. To assess the pathogenicity of the GT-SHZ, conidia collected from H. trionum leaves infected with GT-SHZ were formulated into a spore suspension (1 × 107 spores/mL) and sprayed onto the leaf surfaces of six healthy plants, with six non-inoculated plants as controls. Both groups were placed in two growth chambers with consistent environmental conditions (25°C temperature and 60% humidity). Twelve days post-inoculation, a large amount of white powder appeared on the leaves of the inoculated plants, while the controls remained healthy. The morphological characteristics and the nucleotide sequences of the ITS, 28S rDNA, and TUB2 from the fungus collected on the inoculated leaves are consistent with the GT-SHZ. Two pathogenicity tests obtained similar results, identifying G. tabaci as the pathogen causing powdery mildew on H. trionum. This pathogen has been reported on ","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143414934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First Report of Target Spot Caused by <i>Corynespora cassiicola</i> on <i>Senna obtusifolia</i> L. (Sicklepod) in the United States.","authors":"Sejal Patel, Kira L Bowen, Jenny Koebernick","doi":"10.1094/PDIS-12-24-2541-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-12-24-2541-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Sicklepod (Senna obtusifolia L.) is a weed native to the American tropics which has become widespread in the southeastern United States, posing a significant challenge for row crop producers (McKinnon et al. 2012; Nice 1999). In August 2024, a foliar disease was observed on sicklepod throughout cotton (Gossypium hirsutum L.) plots in a nine-acre field at EV-Smith Plant Breeding Unit in Tallassee, Alabama (32.4967° N, 85.8905° W), U.S. The symptoms were round to irregular, 3 to 9 mm, brown to dark-brown lesions with alternating concentric rings, surrounded by a pale-yellow halo. The estimated disease incidence was 40%. Four symptomatic plants were sampled from different locations across the field for pathogen isolation. The leaves with lesions were surface sterilized by soaking in 1 % NaClO for 1 min, followed by 70 % ethanol for 1 min, and rinsed twice in sterile distilled water for 30 seconds. The lesions were excised and plated on V8 agar amended with 0.5 mL of lactic acid per 500 mL of medium. The plates were incubated at 22 °C under a 12-h light/dark cycle for ten days. Six fungal isolates with identical morphologies were obtained. During incubation, colonies developed gray aerial mycelium, turning dark gray to brown with age. The conidiophores were unbranched, erect or slightly curved, elongated, and brown, appearing singly or in clusters, with 3 to 14 pseudosepta. Conidia were obclavate to cylindrical to slightly curved, and multinucleate, containing 3 to 12 septa. Conidia were 50 to 193 µm in length and 5 to 14 µm in width. For molecular identification of pathogen, isolate SP1 was selected, and DNA was extracted from 100 mg of 10-day-old mycelium using the EZNA Fungal DNA Mini Kit (Omega Bio-tek, GA). Three regions, internal transcribed spacer (ITS; White et al. 1990), actin-encoding locus (act1; Carbine & Kohn, 1999), and hypervariable loci (ga4; Dixon et al. 2009) were used to confirm SP1 isolate. The sequences of ITS (PQ536090) and act1 (PQ876357) shared 100% identity, and 94.7% and 99.3% homology with ITS (ON316921) and act1 (MF320391), respectively. The ga4 sequence (PQ876356) shared 98% identity and 98.09% coverage with C. cassiicola (MH605239) in GenBank. For pathogenicity test, a conidial suspension of isolate SP1 (40,000 spores/mL) was sprayed onto sicklepod plants at the two-true-leaf stage in the greenhouse. Six plants were inoculated with the conidial suspension, while three additional plants were sprayed with sterile distilled water to serve as controls. Control and inoculated plants were transferred to a mist chamber constructed with PVC pipe (dimensions: 4 m × 4 m × 8 m) and enclosed with a transparent plastic sheet. The plants were arranged in a completely randomized design inside the chamber, and a mist system operated for 2 seconds every 10 minutes over three days to maintain humidity above 80%. Initial symptoms on the inoculated leaves were noted seven days post-inoculation, whereas no symptoms were observed on con","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143414937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification, Characterization, and Fungicide Sensitivity of Botryosphaeriaceae Fungi Associated with Avocado Branch Canker Disease in Southern California.","authors":"Valentina Valencia Bernal, Zahra Pegahrad, Mehdi Kamali Dashtarzhaneh, Fatemeh Khodadadi","doi":"10.1094/PDIS-12-24-2674-RE","DOIUrl":"https://doi.org/10.1094/PDIS-12-24-2674-RE","url":null,"abstract":"<p><p>Avocado branch canker disease, caused by Botryosphaeriaceae fungi, threatens avocado (<i>Persea americana</i> Mill.) production in California, reducing yield and orchard lifespan. To effectively manage avocado branch canker, it is imperative to identify the causal fungal species accurately and understand their biology and pathogenic potential. Over 500 fungal isolates were collected from symptomatic branches of avocados showing a general decline, including cankers and dieback of arms and twigs across several California orchards (n=23). Seventy-one representative isolates were selected for detailed analysis based on location, tissue type, colony morphology, and spore characteristics. Multi-locus phylogenetic analysis identified four Botryosphaeriaceae species: <i>Neofusicoccum luteum</i> (most prevalent, 66 isolates), <i>Lasiodiplodia theobromae</i> (3 isolates), <i>Botryosphaeria dothidea</i> (1 isolate), and <i>Neofusicoccum australe</i> (1 isolate). Pathogenicity tests revealed significant variability in aggressiveness, with <i>L. theobromae</i> (26.3 ± 3.77 mm) and <i>N. luteum</i> (23.6 ± 0.87 mm) causing the largest lesions. Additionally, a sporulation trial on an <i>N. australe</i> isolate revealed that acidified potato dextrose agar amended with sterilized pine needles at 22°C under constant light optimized its sporulation. In vitro fungicide assays identified fluazinam as the most effective fungicide across the species exhibiting the lowest EC₅₀ values. Metconazole and propiconazole also exhibited low EC₅₀, while azoxystrobin and boscalid showed the highest. Furthermore, <i>L. theobromae</i> showed reduced sensitivity to azoxystrobin (18.711 μg/mL), cyproconazole (6.381 μg/mL), flutriafol (4.151 μg/mL), and pyraclostrobin (5.477 μg/mL). These findings highlight the importance of species-specific identification and provide critical insights for integrated disease management strategies.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143414940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First Report of <i>Neocosmospora pseudensiformis</i> Causing Bark Cracking on <i>Artocarpus heterophyllus</i> L. in China.","authors":"Xue Min Liu, Tao Li, Ming Rui Huang, Le Feng, Jing Song Guo, Run Hua Yi, Feng Feng","doi":"10.1094/PDIS-11-24-2370-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-11-24-2370-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Jackfruit (Artocarpus heterophyllus) is a tree of the Moraceae family and widely cultivated due to its fruit with diverse medicinal and nutritional properties in China. In June 2022, a serious bark cracking disease was observed on jackfruit in the 2400-acre orchards of Hekou, Yunnan (E103°52'39″ N22°34'14″). The disease mainly harms tree trunks and branches. The incidence rates were about 90% and the mortality rate of plants reached up to 50%. Symptoms initially appeared as small watered-spots with gumming. Subsequently the bark rotted and cracked, the xylem gradually turned brown (Figure 1). Ultimately, the upper branches of infected parts withered and died. Small 5×5 mm segments of infected tissue from 50 randomly selected trunk with typical symptoms were surface sterilized with 75% alcohol solution and 3% hydrogen peroxide solution respectively, rinsed three times with sterile water, and placed onto PDA medium with 50mg/L of penicillin. The plates were kept at 25 to 28 ℃ in the dark. Fusarium-like colonies were consistently isolated on potato dextrose agar (PDA) and 15 monoconidial isolates were obtained. On PDA, colonies exhibited white and fluffy aerial mycelia. Main hyphae are up to 5.5 µm wide. The microconidia were hyaline, falcate, measuring 4.50-9.00×2.30-4.00 µm (av.6.50×3.15 µm, n=50). Macroconidia with septation were 9.00-11.50×3.05-5.25 µm (av.10.50×4.15 µm, n=50) with foot-shaped basal cells, tapering to hooked apical cells (Figure 2). These morphological characterizations were similar to Fusarium sp. (Sun et al, 2018). For further identification, the internal transcribed spacer (ITS) region, RNA polymerase II subunit (RPB2) and translation elongation factor 1-alpha (tef1) genes sequence of isolate BLM1 and BLM2 were amplified and sequenced with primer pairs of ITS1/ITS4, RPB2-5F2/RPB2-7CR, EF-1/EF-728R respectively (Weir et al, 2012), The sequences were submitted to GenBank (ITS: PQ394640 and PQ394641, RPB2: PQ416997 and PQ416998, TEF: PQ416999 and PQ417000). Blast results showed the sequences of BLM1 and BLM2 had high identity to these of Neocosmospora pseudensiformis (Anamorp: Fusarium pseudensiformis) ex-type CBS 125729 (NRRL 46517) (ITS: 548/553(99%); TEF: 456/466(98%); RPB2: 823/823(100%)) (Sandoval-Denis, et al 2019). Polyphasic identification showed above 98% sequence similarity to N. pseudensiformis CBS 125729, CBS 130.78, NRRL22354, LC13838 (https://www.fusarium.org/Poly%20ID%20Fusarium). Phylogenetic analysis using MEGA 7 based on the combined ITS-TEF-RPB2 sequence data, employing the maximum likelihood (ML) method for the multi-locus dataset, showed that BLM1 and BLM2 clustered with F. pseudensiformis (Figure 3). Two five-year-old healthy Jackfruit trees and ten one-year-old seedlings were used for a pathogenicity test. Three plants were inoculated with PDA medium or with sterile water as an experimental control. The seedlings were cultured in a greenhouse (25℃, 70% relative humidity, 12 h light and dark cycle) an","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143414919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}