cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14279225.v1
title: Root and Stem Rot by Phytophthora sojae Kaufm. & Gerd. in the eastern high plains of Meta Department.

description: ABSTRACT The oomycete Phytophthora sojae has been reported to cause “Damping off” during pre and post-emergence, as well as root and stem rot in soybean crops worldwide. The increase in the soybean planted area in Colombia, in the region of eastern high plains of Meta Department, and the presence of highly favorable environmental conditions led to the appearance of seedling damage symptoms, which could be caused by a pathogen complex that includes P. sojae. This study aimed to identify the causal agent of root and stem rot in soybean crops in the region of Meta Department through microbiological and molecular diagnosis of 84 affected tissue samples. Morphological characterization of the causal agent and macroscopic characterization of colonies were performed in modified V8 medium. Molecular identification was done by amplification of the ITS region. Phylogenetic comparison employed ITS sequences reported in previous studies and deposited in the GenBank for different species of the genus Phytophthora, isolates of the species P. sojae from different geographical regions and the sequences of P. sojae obtained in this study. Of the 84 samples analyzed during 2015-2017, seven (7) samples corresponding to 8% showed typical symptoms of root and stem rot, which were attributed to P. sojae, confirming Koch’s postulates. The remaining 77 samples corresponding to 92% presented symptoms of the “Damping off” complex and were associated with Pythium spp. and Fusarium spp. This is the first report of the presence of P. sojae and its participation as a causal agent of root and stem rot in commercial areas of soybeans in the eastern high plains of Meta Department.
DOI: 10.6084/m9.figshare.14279227.v1
title: Elaboration and validation of a digrammatic scale to evaluate soybean bacterial pustule

description: ABSTRACT Bacterial pustule, caused by the bacterium Xanthomonas axonopodis pv. glycines, is considered one of the most important bacterial diseases affecting soybean. The aim of this study was to develop and validate a diagrammatic scale for assessing the severity of soybean bacterial pustule. To elaborate the scale, soybean leaflets with different severity levels were collected to determine the maximum and minimum values of disease severity, while intermediate levels were established according to Weber-Fechner law of visual stimulus. The values proposed for the scale were 1.4%, 3%, 6%, 9%, 20% and 29.5%. To validate the scale, eight evaluators, with no experience in bacterial pustule evaluation, assessed 39 photos of leaflets with different severity levels, without and with the aid of the scale. The results of severity estimated by the evaluators were related to the actual severity values (determined with Assess 2.0 software from digital images of leaves with symptoms) and analyzed with simple linear regressions to assess the accuracy of evaluators. The precision of evaluators was determined based on the coefficients of determination and the variance in absolute errors. Estimates using the proposed diagrammatic scale indicated a significant increase in the coefficient of determination and lower variance in absolute errors, providing greater precision and accuracy of evaluations, which could be adopted to assess the severity of soybean bacterial pustule.
DOI: 10.6084/m9.figshare.14279230.v1
title: Fungal diseases in grapevines cultivated in open field and under waterproof cover

description: ABSTRACT The use of protected cultivation in grapevines has increased with the aim of reducing the occurrence of fungal diseases. Therefore, an experiment was carried out with the cultivars ‘Isabel’, ‘Isabel Precoce’, ‘Bordô’ and ‘Concord’ produced in sequential summer and winter crop seasons and managed in open field and under waterproof plastic cover, without fungicide application. The aim of this study was to verify the severity of the major fungal diseases (downy mildew, anthracnose, leaf spot and grape vine rust) and defoliation under those conditions. The use of plastic cover, during both the summer and the winter crop seasons, reduces the severity of the main fungal diseases and defoliation for the evaluated grapevine cultivars. ‘Bordô’ showed higher tolerance to fungal diseases when compared to the other cultivars. Yield values for vines managed under protected cultivation were higher than those found for vines grown in open field.
DOI: 10.6084/m9.figshare.14279234
title: Populational fluctuation of Cercospora beticola conidia in the air and its relationship with the severity of Cercospora leaf spot of beets

description: ABSTRACT In a field trial in 2016 and 2017, the fluctuation of Cercospora beticola conidia was quantified, as well as its relationship with the severity of Cercospora leaf spot in beets. Beet seeds of cultivar Boro were sown in four replicates, resulting in the evaluation of 80 plants. Conidia were collected by a “vane”-type spore trap containing a microscopic slide smeared with petroleum jelly, which was weekly quantified under a microscope. The disease severity was analyzed through a diagrammatic scale to evaluate the percentage of leaf area affected by the disease. The number of conidia and the severity of Cercospora leaf spot of beets were subjected to the calculation of Pearson correlation coefficient (r). In 2016 and 2017, the collection of conidia occurred concomitantly with the manifestation of the disease, probably because there was inoculum concentration in the air. The correlation between the variables fluctuation of conidial population and disease severity was significant, showing r=0.762 and r=0.768 for 2016 and 2017, respectively. The severity of the disease in beets is influenced by the presence of conidia collected from the air.
DOI: 10.6084/m9.figshare.14279234.v1
title: Populational fluctuation of Cercospora beticola conidia in the air and its relationship with the severity of Cercospora leaf spot of beets

description: ABSTRACT In a field trial in 2016 and 2017, the fluctuation of Cercospora beticola conidia was quantified, as well as its relationship with the severity of Cercospora leaf spot in beets. Beet seeds of cultivar Boro were sown in four replicates, resulting in the evaluation of 80 plants. Conidia were collected by a “vane”-type spore trap containing a microscopic slide smeared with petroleum jelly, which was weekly quantified under a microscope. The disease severity was analyzed through a diagrammatic scale to evaluate the percentage of leaf area affected by the disease. The number of conidia and the severity of Cercospora leaf spot of beets were subjected to the calculation of Pearson correlation coefficient (r). In 2016 and 2017, the collection of conidia occurred concomitantly with the manifestation of the disease, probably because there was inoculum concentration in the air. The correlation between the variables fluctuation of conidial population and disease severity was significant, showing r=0.762 and r=0.768 for 2016 and 2017, respectively. The severity of the disease in beets is influenced by the presence of conidia collected from the air.
DOI: 10.6084/m9.figshare.14279237
title: Sensitivity of populations of Phakopsora pachyrhizi to the fungicide prothioconazole

description: ABSTRACT Reduced efficiency of synthetic fungicides is associated with the selection of individuals presenting genetic alterations that provide resistance to active ingredients. Signs of variations in the frequency of resistant individuals among fungal populations can be quantified based on the effective concentration 50 (CE50). The objective of this study was to evaluate the sensitivity to prothioconazole (DMI) by populations of Phakopsora pachyrhizi collected during the 2017/18 harvest from different soybean producing regions, based on the effective concentration that results in 50% control efficiency (CE50). Soybean leaflets were treated with a.i. at the concentrations zero; 0.0625; 0.125; 0.25; 0.5; 1; 2; 4; 8 and 16 mg L-1 and inoculated with P. pachyrhizi uredospores from 17 localities distributed in Brazil and Paraguay. The inoculated leaflets were kept in 15cm-diameter plastic Petri dishes containing moistened filter paper and incubated in growth chambers at 23 ± 2°C. The disease severity was evaluated 15 days after inoculation. Log-logistic adjustment was employed to estimate the effective concentration that had 50% control efficiency (CE50) for each population. There was variation in the sensitivity of P. pachyrhizi populations to the fungicide prothioconazole, and CE50 values ranged from 0.05 mg L-1 to 1.04 mg L-1 with mean and median values of 0.35 mg L-1. According to the obtained results, sensitivity of P. pachyrhizi to the fungicide prothioconazole varied with the origin of the fungal populations.
DOI: 10.6084/m9.figshare.14279237.v1
title: Sensitivity of populations of Phakopsora pachyrhizi to the fungicide prothioconazole

description: ABSTRACT Reduced efficiency of synthetic fungicides is associated with the selection of individuals presenting genetic alterations that provide resistance to active ingredients. Signs of variations in the frequency of resistant individuals among fungal populations can be quantified based on the effective concentration 50 (CE50). The objective of this study was to evaluate the sensitivity to prothioconazole (DMI) by populations of Phakopsora pachyrhizi collected during the 2017/18 harvest from different soybean producing regions, based on the effective concentration that results in 50% control efficiency (CE50). Soybean leaflets were treated with a.i. at the concentrations zero; 0.0625; 0.125; 0.25; 0.5; 1; 2; 4; 8 and 16 mg L-1 and inoculated with P. pachyrhizi uredospores from 17 localities distributed in Brazil and Paraguay. The inoculated leaflets were kept in 15cm-diameter plastic Petri dishes containing moistened filter paper and incubated in growth chambers at 23 ± 2°C. The disease severity was evaluated 15 days after inoculation. Log-logistic adjustment was employed to estimate the effective concentration that had 50% control efficiency (CE50) for each population. There was variation in the sensitivity of P. pachyrhizi populations to the fungicide prothioconazole, and CE50 values ranged from 0.05 mg L-1 to 1.04 mg L-1 with mean and median values of 0.35 mg L-1. According to the obtained results, sensitivity of P. pachyrhizi to the fungicide prothioconazole varied with the origin of the fungal populations.
DOI: 10.6084/m9.figshare.14279238
title: Temporal and spatial characterization of Botrytis leaf blight of onion

description: ABSTRACT Onion cultivation has intensified due to in natura consumption and industrial processing. However, Botrytis leaf blight (Botrytis squamosa Walker) is the main disease in the seedling period and has compromised the crop. As the epidemiology of the disease in Brazil is unknown, the objective of this study was to characterize the temporal and spatial progression of this disease under cultivation conditions in the southern region of Brazil. Three grams of onion seeds of the cultivar EMPASC 352- Bola Precoce were sown in eight blocks of one square meter each. The initial incidence of the disease at the planting site was used for the spatial analysis through the negative binomial test. The severity of the disease during the cultivation was analyzed based on the percentage of leaf area affected by the disease in ten randomized plants previously demarcated in each replicate and the severity data were adjusted to a nonlinear model throughout the crop cycle. The spatial pattern of the disease was random and the disease progress curve was fitted to the Gompertz model, represented by y = 0.51830 * (exp (5.95660 * exp (-0.47392 * x))). This study will serve as a model for research related to the disease.
DOI: 10.6084/m9.figshare.14279238.v1
title: Temporal and spatial characterization of Botrytis leaf blight of onion

description: ABSTRACT Onion cultivation has intensified due to in natura consumption and industrial processing. However, Botrytis leaf blight (Botrytis squamosa Walker) is the main disease in the seedling period and has compromised the crop. As the epidemiology of the disease in Brazil is unknown, the objective of this study was to characterize the temporal and spatial progression of this disease under cultivation conditions in the southern region of Brazil. Three grams of onion seeds of the cultivar EMPASC 352- Bola Precoce were sown in eight blocks of one square meter each. The initial incidence of the disease at the planting site was used for the spatial analysis through the negative binomial test. The severity of the disease during the cultivation was analyzed based on the percentage of leaf area affected by the disease in ten randomized plants previously demarcated in each replicate and the severity data were adjusted to a nonlinear model throughout the crop cycle. The spatial pattern of the disease was random and the disease progress curve was fitted to the Gompertz model, represented by y = 0.51830 * (exp (5.95660 * exp (-0.47392 * x))). This study will serve as a model for research related to the disease.
DOI: 10.6084/m9.figshare.14279239
title: Integration between genetic and chemical control on the progress of Asian soybean rust and yield

description: ABSTRACT The objective of this study was to evaluate the genetic control integrated to the chemical control of Asian soybean rust (ASR) and the effects of these measures on crop yield. The experiment was conducted in Erechim, Rio Grande do Sul State, Brazil, in 2016/17 and 2017/18 crop years, under a randomized block design, in a subdivided plot scheme (cultivars in the plots and fungicides in the subplots), with four replicates. The following cultivars were used: BMX Vanguarda (without ASR tolerance); TMG 7062; TMG 7262, and TMG 7161, tolerant to ASR (Inox™ Technology cultivars). The fungicides used were: T1) control (without application of fungicides); T2) azoxystrobin + benzovindiflupyr; T3) difenoconazole + cyproconazole; T4) trifloxystrobin + prothioconazole, and T5) epoxiconazole + fluxapyroxad + pyraclostrobin. Four fungicide applications were carried out at the V6, R1, R5.1 and R6 stages. During the experiment, for the calculation of the area under disease progress curve (AUDPC), disease severity was assessed at 7-day intervals in a random sample of 10 trifolia per plot. After harvest, yield components were determined: number of grains per plant, thousand grain weight (g), and yield (kg ha-1). In 2017/18 crop year, the fungicide difenoconazole + cyproconazole was not efficient for ASR control. The soybean cultivars TMG 7062, TMG 7161 and TMG 7261 delayed the disease progression; however, only TMG 7161 presented tolerance in the presence of the inoculum in 2016/17 and 2017/18 crop years. The association between chemical and genetic control is shown to be efficient for ASR control.
DOI: 10.6084/m9.figshare.14279239.v1
title: Integration between genetic and chemical control on the progress of Asian soybean rust and yield

description: ABSTRACT The objective of this study was to evaluate the genetic control integrated to the chemical control of Asian soybean rust (ASR) and the effects of these measures on crop yield. The experiment was conducted in Erechim, Rio Grande do Sul State, Brazil, in 2016/17 and 2017/18 crop years, under a randomized block design, in a subdivided plot scheme (cultivars in the plots and fungicides in the subplots), with four replicates. The following cultivars were used: BMX Vanguarda (without ASR tolerance); TMG 7062; TMG 7262, and TMG 7161, tolerant to ASR (Inox™ Technology cultivars). The fungicides used were: T1) control (without application of fungicides); T2) azoxystrobin + benzovindiflupyr; T3) difenoconazole + cyproconazole; T4) trifloxystrobin + prothioconazole, and T5) epoxiconazole + fluxapyroxad + pyraclostrobin. Four fungicide applications were carried out at the V6, R1, R5.1 and R6 stages. During the experiment, for the calculation of the area under disease progress curve (AUDPC), disease severity was assessed at 7-day intervals in a random sample of 10 trifolia per plot. After harvest, yield components were determined: number of grains per plant, thousand grain weight (g), and yield (kg ha-1). In 2017/18 crop year, the fungicide difenoconazole + cyproconazole was not efficient for ASR control. The soybean cultivars TMG 7062, TMG 7161 and TMG 7261 delayed the disease progression; however, only TMG 7161 presented tolerance in the presence of the inoculum in 2016/17 and 2017/18 crop years. The association between chemical and genetic control is shown to be efficient for ASR control.
DOI: 10.6084/m9.figshare.14279243
title: Control of root rot (Phytophthora cinnamomi) in avocado (Persea Americana) with bioagents

description: ABSTRACT Despite the favorable edaphoclimatic conditions for avocado production in Brazil, diseases such as root rot caused by the pathogen Phytophthora cinnamomi compromise the crop. With the aim of managing root rot in avocado, the present study aimed to evaluate chemical and biological control with isolates of Trichoderma spp. and Pseudomonas fluorescens. Thus, three assays were conducted to assess: (i) mycelial inhibition of P. cinnamomi by isolates of Trichoderma spp. and P. fluorescens from different crop systems; (ii) effect of autoclaved and non-autoclaved metabolites of P. fluorescens, and (iii) chemical or biological treatment of avocado seedlings on the control of root rot under field conditions. The isolates of Trichoderma spp. from maize cultivation soil and the commercial products formulated with Trichoderma presented greater antagonism (p &lt;0.05) to the pathogen P. cinnamomi in the in vitro tests. Similarly, non-autoclaved metabolites of P. fluorescens presented antagonistic potential to control P. cinnamomi. Under field conditions, the fungicide metalaxyl and the bioagents showed effectiveness in controlling P. cinnamomi, as well as greater root length and mass. Results demonstrated potential for the biological control of avocado root rot with Trichoderma spp. and P. fluorescens.
DOI: 10.6084/m9.figshare.14279245
title: Influence of climate factors on Phakopsora euvitis Y. Ono airborne dispersal in grapevine crop

description: ABSTRACT Grape rust, one of the most important diseases of Vitis spp., is managed in Brazil according to a calendar-based fungicide spray program. Despite the use of fungicides, the crop and the quality of grapes have shown significant losses due to rust. This disease causes leaf fall, unequal size and color of berries and loss in plant vigor in the following harvest. The aim of this study was to investigate the relationship between airborne urediniospore dispersal and weather parameters to improve the management of this disease. Thus, vineyards of the cultivar ‘Syrah’, susceptible to grape rust, were monitored to determine Phakopsora euvitis airborne dispersal dynamic. Wind vane spore traps were maintained at 0.5 m above the grapevine canopy and samples were collected every 24 h, while slides were changed at 9:00 a.m. A logistic regression model was developed to estimate the urediniospore dispersal probability. Higher urediniospore concentrations were observed between April and August, while in the remaining months the concentration was low or zero. The regression model of the airborne urediniospore concentration relative to the weather parameters was described as logit (Y) = 15.6668 - 0.6333 (temperature) + 0.4291 (wind speed), and a decision threshold of 0.47 was determined for predictive purposes.
DOI: 10.6084/m9.figshare.14279243.v1
title: Control of root rot (Phytophthora cinnamomi) in avocado (Persea Americana) with bioagents

description: ABSTRACT Despite the favorable edaphoclimatic conditions for avocado production in Brazil, diseases such as root rot caused by the pathogen Phytophthora cinnamomi compromise the crop. With the aim of managing root rot in avocado, the present study aimed to evaluate chemical and biological control with isolates of Trichoderma spp. and Pseudomonas fluorescens. Thus, three assays were conducted to assess: (i) mycelial inhibition of P. cinnamomi by isolates of Trichoderma spp. and P. fluorescens from different crop systems; (ii) effect of autoclaved and non-autoclaved metabolites of P. fluorescens, and (iii) chemical or biological treatment of avocado seedlings on the control of root rot under field conditions. The isolates of Trichoderma spp. from maize cultivation soil and the commercial products formulated with Trichoderma presented greater antagonism (p &lt;0.05) to the pathogen P. cinnamomi in the in vitro tests. Similarly, non-autoclaved metabolites of P. fluorescens presented antagonistic potential to control P. cinnamomi. Under field conditions, the fungicide metalaxyl and the bioagents showed effectiveness in controlling P. cinnamomi, as well as greater root length and mass. Results demonstrated potential for the biological control of avocado root rot with Trichoderma spp. and P. fluorescens.
DOI: 10.6084/m9.figshare.14279248
title: Incidence and molecular characterization of badnavírus in germplasm banks of yam in Brazil

description: ABSTRACT Badnaviruses (family Caulimoviridae) have semicircular dsDNA genomes encapsidated into bacilliform particles. Dioscorea bacilliform virus (DBV) is an important Badnavirus infecting several species of Dioscorea (yam) in the southern hemisphere. In this study, 235 yam leaf samples were collected from different germplasm banks maintained by “Luiz de Queiroz” College of Agriculture (ESALQ/USP), Federal University of Viçosa (UFV) and Federal University of Recôncavo da Bahia (UFRB). The average incidence of badnavirus in the evaluated samples was 75.3%. Molecular and phylogenetic analyses, carried out from 42 nucleotide sequences, of the badnavirus RT/RNaseH region, revealed the occurrence of Dioscorea bacilliform AL virus (DBALV) and Dioscorea bacilliform SN virus (DBSNV) in different yam species. So far, only DBALV has been reported in yams in Brazil, being restricted to the Northeast region. Therefore, this is the first report of DBSNV infecting yam crop in the country. In addition to the episomal species, endogenous sequences were detected, and the percentage of nucleotide identity varied between 89% and 100% with endogenous Dioscorea bacilliform virus (eDBV), belonging to groups 9 and 12. The obtained results corroborate the hypothesis that DBALV and DBSNV are present in yam propagating materials and are widely disseminated in Brazil.
DOI: 10.6084/m9.figshare.14279245.v1
title: Influence of climate factors on Phakopsora euvitis Y. Ono airborne dispersal in grapevine crop

description: ABSTRACT Grape rust, one of the most important diseases of Vitis spp., is managed in Brazil according to a calendar-based fungicide spray program. Despite the use of fungicides, the crop and the quality of grapes have shown significant losses due to rust. This disease causes leaf fall, unequal size and color of berries and loss in plant vigor in the following harvest. The aim of this study was to investigate the relationship between airborne urediniospore dispersal and weather parameters to improve the management of this disease. Thus, vineyards of the cultivar ‘Syrah’, susceptible to grape rust, were monitored to determine Phakopsora euvitis airborne dispersal dynamic. Wind vane spore traps were maintained at 0.5 m above the grapevine canopy and samples were collected every 24 h, while slides were changed at 9:00 a.m. A logistic regression model was developed to estimate the urediniospore dispersal probability. Higher urediniospore concentrations were observed between April and August, while in the remaining months the concentration was low or zero. The regression model of the airborne urediniospore concentration relative to the weather parameters was described as logit (Y) = 15.6668 - 0.6333 (temperature) + 0.4291 (wind speed), and a decision threshold of 0.47 was determined for predictive purposes.