{"title":"Characterization and Pathogenicity of Soilborne Pathogens in <i>Gloriosa superba</i>: Effects of Single- and Multiple-Pathogen Coinfection on Disease Responses.","authors":"Shanmuga Priya Dhanabalan, Iruthayasamy Johnson, Parthiban V Kumaresan, Rajamani Kandasamy, Senthil Natesan, Sambasivam Periyannan, Karthikeyan Muthusamy","doi":"10.1094/PDIS-03-24-0496-RE","DOIUrl":"10.1094/PDIS-03-24-0496-RE","url":null,"abstract":"<p><p>Glory lily (<i>Gloriosa superba</i>), an ornamental climbing plant, contains the bioactive compound colchicine, attracting attention from the pharmaceutical industry. However, soilborne pathogens have emerged as a serious threat to the cultivation of glory lily, leading to substantial economic losses in the southern parts of India. Among these, the three major pathogens are <i>Macrophomina phaseolina</i>, <i>Fusarium oxysporum</i>, and <i>Agroathelia rolfsii</i>, causing dry root rot (also referred to as charcoal rot), wilt, and stem rot, respectively. Here, we characterized these pathogens using morphological characteristics and phylogenetic analysis of DNA sequences related to the internal transcribed spacer of ribosomal DNA, calmodulin (<i>CAL</i>), and translation elongation factor 1-alpha (<i>TEF-1α</i>). Furthermore, in the pathogenicity tests, the inoculation of <i>M. phaseolina</i> alone resulted in lesions measuring 7.54 ± 0.01 mm on tubers and 90% seedling mortality. This severity was comparable to the simultaneous inoculation of all three pathogens, indicating the prominence of dry root rot among soilborne diseases. This study marks the first detailed investigation of soilborne pathogens combined infection in <i>G. superba</i>, contributing to the understanding of fungal disease complexity in medicinal plants.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3279-3287"},"PeriodicalIF":4.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141458691","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}
Plant diseasePub Date : 2024-11-01Epub Date: 2024-10-22DOI: 10.1094/PDIS-12-23-2639-RE
Xiaojing Shi, Soonhong Min, Geunhwa Jung
{"title":"Field Evaluation of Fluazinam Fungicide in Dollar Spot Populations Confirmed In Vitro Insensitivity.","authors":"Xiaojing Shi, Soonhong Min, Geunhwa Jung","doi":"10.1094/PDIS-12-23-2639-RE","DOIUrl":"10.1094/PDIS-12-23-2639-RE","url":null,"abstract":"<p><p>Fluazinam, a fungicide widely used in agriculture and turf management, was traditionally thought to pose a low risk of resistance. However, our in vitro sensitivity test conducted in 2021 revealed reduced sensitivity to fluazinam in dollar spot, highlighting the need for more vigilant field monitoring. In 2022 and 2023, we evaluated the field responses of four <i>Clarireedia jacksonii</i> isolates with varying in vitro sensitivity to fluazinam. Fluazinam was used at both a full labeled rate (0.5 oz/1,000 ft<sup>2</sup>) and a half-rate (0.25 oz/1,000 ft<sup>2</sup>) to evaluate the effectiveness in isolate-inoculated plots in the field. In 2022, both natural and sensitive isolates showed significantly better control compared to insensitive isolates under both half- and full-rate treatments. However, in 2023, half-rate fluazinam demonstrated limited control under high disease pressure, providing relative disease control of dollar spot less than 45% across all treatments. In contrast, full-rate fluazinam maintained significantly better control of natural and sensitive isolates compared with insensitive isolates. Our results, showing that in vitro insensitivity leads to field insensitivity under inoculated conditions, suggest the development of fluazinam insensitivity in the <i>C. jacksonii</i> population. This highlights the need for judicious use of fluazinam and the establishment of continuous resistance monitoring. Furthermore, the loss of control observed when fluazinam was applied at half-rates under high disease pressure highlights the importance of careful fungicide use.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3329-3335"},"PeriodicalIF":4.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141564063","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}
Plant diseasePub Date : 2024-11-01Epub Date: 2024-11-08DOI: 10.1094/PDIS-08-23-1570-RE
Glen Groben, Brian Schaefer, Bruce B Clarke, James A Murphy, Patrick Purdon, Paul Koch, Ning Zhang
{"title":"Horizontal and Vertical Distribution of <i>Clarireedia</i> spp. in Asymptomatic and Symptomatic Creeping Bentgrass Cultivars.","authors":"Glen Groben, Brian Schaefer, Bruce B Clarke, James A Murphy, Patrick Purdon, Paul Koch, Ning Zhang","doi":"10.1094/PDIS-08-23-1570-RE","DOIUrl":"10.1094/PDIS-08-23-1570-RE","url":null,"abstract":"<p><p>Dollar spot is an important disease of both cool- and warm-season turfgrasses caused by six fungal species in the genus <i>Clarireedia</i>, yet the ecology and epidemiology of these pathogens remains poorly understood. The goal of this study was to determine the distribution of <i>Clarireedia</i> in asymptomatic and symptomatic creeping bentgrass (<i>Agrostis stolonifera</i>) in the field using a previously developed quantitative PCR assay. To determine the horizontal distribution of the pathogen, the abundance of <i>Clarireedia</i> spp. was measured in leaf and crown tissue from 90, 1-cm-diameter cores spaced 10 cm apart in May 2019 and 2020 (asymptomatic tissue) and August 2019 and July 2020 (symptomatic tissue). Thirty-seven to 69% of cores sampled from asymptomatic turfgrass and 77 to 95% of cores taken from symptomatic turfgrass yielded positive detections for <i>Clarireedia</i>. Spatial analysis indicated that <i>Clarireedia</i> was randomly distributed in the field in both asymptomatic and symptomatic turfgrass. To assess the vertical distribution of the pathogen, the abundance of <i>Clarireedia</i> was measured in the foliar, crown, and thatch layers of 39, 1-cm-diameter × 2.5-cm-deep cores of creeping bentgrass maintained at fairway height (9.5 mm) during 2019 and 2020. <i>Clarireedia</i> was most abundant in foliar tissue, followed by crown tissue and thatch (lowest abundance) throughout the 2-year study. Both studies provide evidence that <i>Clarireedia</i> is widely distributed in turfgrass swards prior to symptom development and can persist within turfgrass as an endophyte. These findings will improve our understanding of <i>Clarireedia</i> epidemiology and may lead to more sustainable dollar spot management.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3352-3360"},"PeriodicalIF":4.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141604018","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":"Baseline Sensitivity and Toxicity Mechanisms of Prochloraz to <i>Alternaria alternata</i> Strains Associated with Maize Leaf Blight in Heilongjiang Province in China.","authors":"Guijin Shen, Haolin Teng, Jingzheng Sun, Xi Xu, Chenyang Jiao, Xiaoya Fan, Ping Zhou, Xiangjing Wang, Wensheng Xiang, Junwei Zhao","doi":"10.1094/PDIS-04-24-0913-RE","DOIUrl":"10.1094/PDIS-04-24-0913-RE","url":null,"abstract":"<p><p><i>Alternaria</i> species are fungal pathogens that can infect maize, causing leaf blight disease and significant economic losses. This study aimed to determine the baseline sensitivity to prochloraz of <i>A. alternata</i> isolates obtained from diseased maize leaves collected from Heilongjiang Province by assessing the half-maximal effective concentration (EC<sub>50</sub>) values. The EC<sub>50</sub> values of prochloraz ranged from 0.0550 to 2.3258 μg/ml, with an average of 0.9995 ± 0.5192 μg/ml. At EC<sub>50</sub> (1.2495 μg/ml) and 2EC<sub>50</sub> (2.4990 μg/ml), prochloraz increased the number of mycelial offshoots, disrupted the cell membrane integrity of conidia and mycelia, and resulted in a reduced ergosterol content in the mycelia. Prochloraz significantly affected the mycelial cell membrane permeability and increased the malondialdehyde content and superoxide dismutase activity. No cross-resistance was detected between prochloraz and other fungicides. These data demonstrate that prochloraz is a promising fungicide for managing maize leaf blight caused by <i>A. alternata</i> and provide novel insights into understanding the mechanism of prochloraz toxicity against <i>A. alternata</i> isolates.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3336-3344"},"PeriodicalIF":4.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141564062","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}
Plant diseasePub Date : 2024-11-01Epub Date: 2024-11-06DOI: 10.1094/PDIS-12-23-2575-RE
Jinfa Zhao, Song Zhang, Jiajun Wang, Binghai Lou, Yan Zhou
{"title":"Construction of an Infectious Clone of Citrus Chlorotic Dwarf-Associated Virus and Confirmation of Its Pathogenicity.","authors":"Jinfa Zhao, Song Zhang, Jiajun Wang, Binghai Lou, Yan Zhou","doi":"10.1094/PDIS-12-23-2575-RE","DOIUrl":"10.1094/PDIS-12-23-2575-RE","url":null,"abstract":"<p><p>Citrus chlorotic dwarf disease (CCDD) seriously affects the citrus industry. Citrus chlorotic dwarf-associated virus (CCDaV) is speculated to be the causal agent of CCDD. However, this speculation has not been confirmed by fulfilling Koch's postulates. In this study, an infectious clone comprising a 1.6-fold tandem CCDaV genome in the binary vector pBinPLUS was constructed and agro-inoculated into 'Eureka' lemon (<i>Citrus limon</i>) seedlings through vacuum infiltration. At 60 days postinoculation, 25% of the 'Eureka' lemon seedlings developed symptoms of crinkling and curling that were the same as those associated with the wild-type virus. Western blotting and graft transmission assays confirmed that the infectious clone systemically infected 'Eureka' lemon seedlings. In addition, CCDaV can establish infection on three more <i>Citrus</i> species and one hybrid, although at different infection rates. These findings support that CCDaV is the primary causal agent of CCDD. The infectious CCDaV clone will allow further studies on the functions of viral proteins and molecular interactions of CCDaV with its hosts.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3393-3399"},"PeriodicalIF":4.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141634211","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 Stripe Rust Resistance and Chip Detection Resistance Genes in 286 Xinjiang Wheat Cultivars and Breeding Lines.","authors":"Haohao Yan, Jianing Zhu, Yongjin Jin, Xingxuan Bai, Qingdong Zeng, Haifeng Gao, Jinbiao Ma, Lili Huang, Zhensheng Kang, Gangming Zhan","doi":"10.1094/PDIS-04-24-0780-RE","DOIUrl":"10.1094/PDIS-04-24-0780-RE","url":null,"abstract":"<p><p>Wheat stripe rust is a destructive disease worldwide, caused by <i>Puccinia striiformis</i> f. sp. <i>tritici</i> (<i>Pst</i>). Resistance breeding is the most effective method of controlling stripe rust. Xinjiang is a relatively independent epidemic region of wheat stripe rust in China. In recent years, wheat stripe rust in this area has shown an upward trend. Therefore, the purpose of this study was to evaluate the resistance level of wheat cultivars (lines) to the prevalent <i>Pst</i> races and determine the genetic background of stripe rust resistance genes in Xinjiang. Six predominant <i>Pst</i> races in China were used to study resistance of 286 wheat cultivars (lines) at both the seedling stage under controlled conditions and the adult-plant stage under field conditions. In the seedling tests, 175 (61.19%) entries were resistant to the race CYR23, 125 (43.71%) to CYR29, 153 (53.50%) to CYR31, 88 (30.77%) to CYR32, 174 (60.84%) to CYR33, and 98 (34.27%) to CYR34. Among the resistant entries, 23 (8.04%) were resistant to all six races. In the field test, 135 (47.20%) entries were resistant to the tested mixed races. Through comparing the responses in the seedling and adult-plant stages, 109 (38.11%) entries were found to have adult-plant resistance (APR), and 14 (4.90%) entries have all-stage resistance (ASR). The 286 wheat entries were also tested using a wheat breeder chip containing 12 <i>Yr</i> resistance loci. Among these entries, 44 (15.38%) were found to have a single gene, 221 (77.27%) have two or more genes, and 21 (7.34%) have none of the 12 genes, including 144 (50.35%) with <i>Yr30</i> and 5 (1.75%) with <i>YrSP</i>. Entries with two or more genes have stronger resistance to <i>Pst</i>. Overall, the majority of entries have all-stage and/or adult-plant resistance, but their genes for resistance in addition to the 12 tested <i>Yr</i> genes need to be determined. It is also necessary to introduce more effective resistance genes in the breeding programs to improve stripe rust resistance in wheat cultivars in Xinjiang.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3269-3278"},"PeriodicalIF":4.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141470071","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}
Plant diseasePub Date : 2024-11-01Epub Date: 2024-10-16DOI: 10.1094/PDIS-04-24-0869-RE
Johanna Wesche, Zhezheng Zeng, Chao-Xi Luo, Guido Schnabel
{"title":"<i>Pseudomonas chlororaphis</i> Metabolites Reduce <i>MfCYP51</i> Expression and Yield Synergistic Efficacy in Mixture with Reduced Rates of Propiconazole Against DMI-Resistant <i>Monilinia fructicola</i> Isolates.","authors":"Johanna Wesche, Zhezheng Zeng, Chao-Xi Luo, Guido Schnabel","doi":"10.1094/PDIS-04-24-0869-RE","DOIUrl":"10.1094/PDIS-04-24-0869-RE","url":null,"abstract":"<p><p>Brown rot caused by <i>Monilinia fructicola</i> is one of the most important diseases affecting peach production in the southeastern United States. Management often involves the use of demethylation inhibitor (DMI) fungicides, but efficacy can be compromised because of overexpression of the <i>MfCYP51</i> gene encoding the 14α-demethylase of the ergosterol biosynthesis pathway. This study aimed to investigate the influence of the biorational fungicide Howler EVO containing <i>Pseudomonas chlororaphis</i> ASF009 metabolites on the expression of <i>MfCYP51</i> in <i>M. fructicola</i> and associated synergy with a DMI fungicide for control of DMI-resistant strains. Mycelia from two DMI-sensitive and three DMI-resistant <i>M. fructicola</i> isolates were exposed or not to propiconazole (0.3 μg/ml), Howler (88.1 μg/ml), or the combination propiconazole + Howler for 6 h prior to RNA extraction. Real-time PCR indicated that Howler reduced the constitutive expression of <i>MfCYP51</i> in DMI-sensitive and two of three DMI-resistant isolates. Propiconazole-induced expression of the DMI target gene was significantly reduced by Howler and by the mixture of Howler plus propiconazole in all isolates. Detached fruit studies on apple revealed that the combination of Howler plus a reduced label rate of Mentor (50 μg/ml propiconazole) was synergistic against brown rot caused by a DMI-resistant isolate in high and low inoculum spore concentration experiments (synergy values of 40.1 and 4.9, respectively). We hypothesize that the synergistic effects against <i>M. fructicola</i> resistant to DMI fungicides based on <i>MfCYP51</i> gene overexpression can be attributed to reduced 14α demethylase production due to transcription inhibition, which may necessitate fewer DMI fungicide molecules to arrest fungal growth. The use of Howler/DMI mixtures for brown rot control warrants further investigation because such mixtures could potentially allow for reduced DMI fungicide use rates in the field without compromising yield or increased resistance selection.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3311-3318"},"PeriodicalIF":4.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141492996","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}
Plant diseasePub Date : 2024-11-01Epub Date: 2024-10-30DOI: 10.1094/PDIS-06-23-1210-SR
Davide Greco, Erika Sabella, Giambattista Carluccio, Mariarosaria DePascali, Eliana Nutricati, Luigi De Bellis, Andrea Luvisi
{"title":"Could Pistachio (<i>Pistacia vera</i>) Be a Suitable Alternative Crop for Olive-Growing Mediterranean Areas Affected by <i>Xylella fastidiosa</i> subsp. <i>pauca</i> ST53?","authors":"Davide Greco, Erika Sabella, Giambattista Carluccio, Mariarosaria DePascali, Eliana Nutricati, Luigi De Bellis, Andrea Luvisi","doi":"10.1094/PDIS-06-23-1210-SR","DOIUrl":"10.1094/PDIS-06-23-1210-SR","url":null,"abstract":"<p><p>In the olive-growing areas of Apulia (southern Italy) where <i>Xylella fastidiosa</i> has caused enormous damage, there is a need to identify alternative crops. These could include pistachio (<i>Pistacia vera</i> L.), but it is critical to define the impact of the bacterium on this crop and what are the main phytosanitary threats for this species in the areas where the bacterium is now endemic. Therefore, we started evaluating infections caused by <i>X. fastidiosa</i>, the fungus <i>Neofusicoccum mediterraneum</i>, and other pathogens on four pistachio cultivars ('Kerman', 'Aegina', 'Lost Hills', and 'Napoletana') grown in areas where <i>X. fastidiosa</i> has been present for a long time. <i>X. fastidiosa</i> was detected only in one orchard (incidence: 18% 'Napoletana' and 55% 'Kerman') out of six surveyed orchards, with low bacterium concentration (1.67 to 5.98 × 10<sup>3</sup> CFU ml<sup>-1</sup>) and no symptoms. <i>N. mediterraneum</i> was retrieved in three orchards just on the cultivar Kerman but with high incidence (up to 30%) and infection level quantified as molecular severity (6.82 to 7.43); no other pathogens were detected. The <i>N. mediterraneum</i> representative isolates characterized in this study showed similarity with Spanish and Portuguese isolates. A confocal microscope analysis for this host-pathogen association suggested no differences in plant response to fungal aggression between the cultivars Kerman and Aegina, but just lack of latent inoculum in 'Aegina' plants, pointing to a possible nursery origin of the infection. Waiting for additional targeted experiments to clearly define host response of pistachio cultivars to <i>Xylella</i> spp., this study also points at <i>N. mediterraneum</i> as a potential threat to this tree crop new for the area.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3222-3233"},"PeriodicalIF":4.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546750","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}
Plant diseasePub Date : 2024-11-01Epub Date: 2024-10-24DOI: 10.1094/PDIS-04-24-0756-RE
Susan J Sprague, Angela P Van de Wouw, Stephen J Marcroft, Abebayehu G Geffersa, Alexander Idnurm, Luke G Barrett
{"title":"Host Genetic Resistance in <i>Brassica napus</i>: A Valuable Tool for the Integrated Management of the Fungal Pathogen <i>Leptosphaeria maculans</i>.","authors":"Susan J Sprague, Angela P Van de Wouw, Stephen J Marcroft, Abebayehu G Geffersa, Alexander Idnurm, Luke G Barrett","doi":"10.1094/PDIS-04-24-0756-RE","DOIUrl":"10.1094/PDIS-04-24-0756-RE","url":null,"abstract":"<p><p>Management of plant disease in agro-ecosystems ideally relies on a combination of host genetic resistance, chemical control, and cultural practices. Growers increasingly rely on chemical and genetic options, but their relative benefits in disease control, yield, and economic outcomes are rarely quantified. We explore this relationship for blackleg crown canker disease (caused by <i>Leptosphaeria maculans</i>), a major biotic constraint limiting canola production globally. Data from 20 field trials conducted from 2013 to 2015 in canola-growing regions of Australia were used to assess the effects of host resistance and fungicide treatment on blackleg severity, grain yield, and gross margin. In the absence of fungicide, blackleg disease was 88% lower in the most resistant compared with the most susceptible blackleg resistance category. In the most susceptible resistance category, the most effective fungicide treatment significantly reduced blackleg severity (from 50 to 6%) and increased grain yield (478 kg/ha, 41%) and gross margin (AU$120/ha, 17%). However, the mean benefits of fungicide tended to decrease with increasing levels of genetic resistance, to the point that yield, disease, and gross margin benefits were close to zero in the most resistant cultivars. Overall, these findings suggest that fungicides can reduce blackleg severity, but the benefits of application strongly depend on associated levels of genetic resistance. Canola cultivars with higher genetic resistance reliably reduced blackleg disease and maintained grain yield without the associated cost of fungicide application. The intensification of canola production to meet increasing global demand will require strategies to sustainably manage and protect finite genetic resistance resources to control blackleg disease.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3319-3328"},"PeriodicalIF":4.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141493020","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}
Plant diseasePub Date : 2024-11-01Epub Date: 2024-11-08DOI: 10.1094/PDIS-10-23-2247-RE
Clive H Bock, David I Shapiro-Ilan, Michael W Hotchkiss, Pedro F S Toledo, Lenny Wells, Jason M Schmidt, Cristina Pisani, Angelita L Acebes-Doria
{"title":"Scab Intensity in Pecan Trees in Relation to Hedge-Pruning Methods.","authors":"Clive H Bock, David I Shapiro-Ilan, Michael W Hotchkiss, Pedro F S Toledo, Lenny Wells, Jason M Schmidt, Cristina Pisani, Angelita L Acebes-Doria","doi":"10.1094/PDIS-10-23-2247-RE","DOIUrl":"10.1094/PDIS-10-23-2247-RE","url":null,"abstract":"<p><p>Pecan is a valuable nut crop cultivated in the southeastern United States. Among the major yield-limiting factors in the region is scab, caused by the plant pathogenic fungus <i>Venturia effusa</i>. Managing scab in tall trees (15 to 25+ m) in pecan orchards is challenging because of the limitations of getting sufficient spray coverage throughout the canopy. We explored the effects of hedge pruning on scab in three orchards: 14-m-tall cv. Desirable trees winter hedge pruned on alternate sides to 11 m (site 1), 18-m-tall cv. Stuart trees hedge pruned on both sides simultaneously to 11 m (site 2), and 15-m-tall cv. Caddo trees winter hedge pruned in winter versus summer to 11 m (site 3). At site 1 and 2, hedge-pruned trees were compared with nonpruned control trees. All trees received recommended fungicide applications to control scab via an air-blast sprayer. Disease incidence and/or severity was assessed at different sample heights on shoots, foliage, and fruit during three seasons (2020, 2021, and 2022). At site 1 the hedge-pruned trees often had significantly or numerically more severe scab on foliage and fruit compared with the control trees, although the differences were mostly small. The frequency of mature fruit with scab severity <10% was greatest on control trees in 2021 and 2022. At site 2, there were few differences between hedge-pruned and control trees (on fruit, scab severity was either significantly less on hedge-pruned trees or not different from the control), but the frequency of mature fruit with scab severity <10% was consistently greatest on hedge-pruned trees. At site 3, scab intensity was low, and there were no significant differences in scab severity between winter- and summer-pruning treatments. At sites 1 and 2, there was generally more severe scab at greater sample heights compared with low in the canopy. At site 3 there was little effect of height on disease. The benefit of hedge pruning likely increases with tree height in scab-susceptible cultivars. If a tree is taller than ∼15 m, a greater proportion of the fruit will be within reach of efficacious spray coverage from air-blast sprayers.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3381-3392"},"PeriodicalIF":4.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141727609","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}