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BACKGROUND: In addition to the inherent challenges of their condition, children with autism spectrum disorder (ASD) are also susceptible to the global obesity epidemic. However, concerning the prevalence of obesity within the Moroccan ASD pediatric population, data remain scarce. METHODS: A total of 258 children (boys = 195) aged 6 to 12 years old (mean = 9.4 ± 1.4) diagnosed with ASD participated in this study. Besides the body mass and height, four significant anthropometric markers for assessing obesity were examined: body mass index (BMI), body surface area (BSA), waist circumference (WC), and waist-to-height ratio (WHtR). Each anthropometric marker was categorized into one of three cardiometabolic risk levels based on the Z-scores and their corresponding percentiles. The distribution was as follows: low risk (≤84th percentile), high risk (85th-94th percentile), and very high risk (≥95th percentile). Subsequently, a multiple regression analysis was employed to develop an algorithm that generates a composite risk score. This score incorporates all the anthropometric variables simultaneously, while also weighting their individual contributions to the cardiometabolic risk. RESULTS: Children with ASD exhibit an anthropometric profile that markedly increases their susceptibility to cardiometabolic issues. While roughly 11% of the general Moroccan child population is overweight or obese, this figure soars to nearly 60% among children with ASD when considering the central adiposity markers. Furthermore, children from middle-class socioeconomic backgrounds display a more than threefold greater risk of developing overweight or obesity compared to their counterparts from lower socioeconomic backgrounds. CONCLUSIONS: This study has, for the first time, provided an up-to-date overview of the cardiometabolic risk in Moroccan children with ASD using traditional anthropometric measurements. The primary risk factor is clearly linked to central (abdominal) adiposity, which is recognized as the most deleterious. This study highlights the need to include general and central obesity markers. This study underscores the importance of incorporating both general and central adiposity markers for a more comprehensive assessment, and it emphasizes the need for closer monitoring within this high-risk population.
Subject(s)
Autism Spectrum Disorder , Overweight , Humans , Autism Spectrum Disorder/epidemiology , Male , Female , Morocco/epidemiology , Child , Prevalence , Overweight/epidemiology , Anthropometry , Socioeconomic Factors , Pediatric Obesity/epidemiology , Waist Circumference , Body Mass IndexABSTRACT
BACKGROUND: Adolescents who experience overweight or obesity commonly persist in these conditions into adulthood, thereby elevating their vulnerability to health issues. The focus of this study is on health risk markers such as body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), body surface area (BSA), and cardiorespiratory fitness (CRF). The objectives include updating normative values for BMI, WC, WHtR, and BSA in Canadian adolescents, establishing cardiometabolic risk zones, and developing a composite score considering both anthropometric and CRF markers. METHODS: Involving 1864 adolescents, the study used the LMS method to generate percentile norms, stratified by age and sex. Cardiometabolic risk zones were established for each marker based on Z-scores, and a composite score was created. RESULTS: An increase in WC of 5.8 and 7.4 cm for boys and girls, respectively, was observed since 1981. Forward multiple regression analyses were conducted to assess the robustness and validity of the proposed model. The results indicated that the model explained nearly 90% (R2 = 0.890) of the common variance between the composite score and the retained independent variables. Moreover, the model demonstrated a mean absolute error (MAE) of approximately 6 percentiles, confirming its high precision. Furthermore, these analyses yielded key thresholds for identifying adolescents at risk: the 70th percentile for high cardiometabolic risk and the 85th percentile for very-high risk. CONCLUSIONS: Individually, WC or WHtR seem to be better markers for evaluating cardiometabolic risk than BMI during adolescence. However, CRF showed comparable importance to anthropometric markers in determining cardiometabolic risk. The simultaneous inclusion of anthropometric and CRF markers provides a better picture of the global cardiometabolic risk in adolescents.
Subject(s)
Cardiorespiratory Fitness , Overweight , Humans , Adolescent , Male , Female , Canada , Body Mass Index , Anthropometry , Waist Circumference , Waist-Height Ratio , Pediatric Obesity , ChildABSTRACT
The Association of Southeast Asian Nations (ASEAN), a new global economic force, has struggled to achieve a dual objective of enhanced economic growth and improved environmental quality. Financial development is generally considered an important tool in achieving these simultaneous objectives. This paper examines the response mechanism and the inter-relationship between the ASEAN region's financial development, energy consumption, and economic growth. Unlike previous studies, the paper uses a generalized method of moments panel vector autoregression (GMM-panel VAR) framework for the 1981-2021 period. The second-generation Granger causality test is used to identify their causality relationship. Economic growth supports financial development and reduces energy consumption from fossil fuel sources in the ASEAN countries. Financial development also reduces fossil fuel energy consumption. The bi-directional relationship between economic growth and fossil fuel energy consumption exists. Energy consumption and financial development are also bi-directionally linked. However, only the unidirectional Granger causality from economic growth to financial development is found. The variance decomposition analysis results confirm that economic growth accounts for the most significant variance in fossil fuel energy consumption and financial development in the ASEAN countries. Policy implications have emerged based on these findings.
Subject(s)
Carbon Dioxide , Economic Development , Carbon Dioxide/analysis , Asia , Energy-Generating Resources , Fossil Fuels , Renewable EnergyABSTRACT
BACKGROUND: The efficacy of drip-applied nematicides depends on adequate product distribution, which can be difficult in sandy soils. Three new non-fumigant nematicides (fluazaindolizine, fluensulfone, fluopyram), together with two old nematicides, oxamyl and metam potassium, were evaluated when applied via single and double drip tapes to control root-knot nematode in cucumber and squash in Florida between February 2020 and December 2022. RESULTS: Nematicide applications via double drip tapes resulted in lower root gall infection (and tend to have higher yield) as compared to a single tape for fluopyram, but no difference was noted between single and double tapes for oxamyl and fluazaindolizine. Fluensulfone response was somewhere in between and metam potassium had higher squash yield when applied with double tapes. Root-knot infection was higher in cucumber than in squash, and metam potassium had the highest yields and lowest nematode infection compared to other nematicide treatments. CONCLUSION: The benefit of double versus single drip tapes depended on the type of nematicide that was applied and was evident for nematicides that have poor water solubility like fluopyram. Some benefit was noted for metam potassium, but no or limited benefit was noted for oxamyl, fluazaindolizine and fluensulfone. © 2023 Society of Chemical Industry.
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Globe artichoke (Cynara cardunculus var. scolymus L.) is a new alternative crop in Florida. This long-season crop poses a very high risk of root-knot nematode (RKN) damage, the most important nematode problem in vegetable production in Florida. This study aimed to examine the impact of RKN damage on artichoke production in the subtropical climate of Florida. Treatments consisted of four cultivars ('Green Globe Improved', 'Green Queen', 'Imperial Star', and 'Opal') planted on three different dates (October 5, October 19, and November 2) in Experiment 1, and three cultivars ('Green Globe Improved', 'Green Queen', and 'Imperial Star') grown with or without vernalization using gibberellic acid (GA3) in Experiment 2. Both field experiments were conducted on sandy soil in west-central Florida during the 2020-2021 and 2021-2022 growing seasons. We collected RKN population density and gall index (GI) data to assess RKN damage. In Experiment 1, all tested cultivars showed moderate to high RKN infection in the 2021-2022 season, with 43% to 75% of roots galled. There was no effect of planting dates on RKN damage in the 2020-2021 season. However, delaying the planting date from October 5 to November 2 reduced the RKN damage while increasing the RKN population densities in the 2021-2022 season. In Experiment 2, all tested cultivars showed high RKN infestation, with more than 80% of roots galled. Vernalization by GA3 did not affect the severity of RKN damage. Our results suggest that all tested artichoke cultivars are highly susceptible to RKN in subtropical environments of Florida, raising an alarm on the risk of RKN damage to commercial artichoke production and increasing awareness about the need for RKN management.
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OBJECTIVE: The main objective of this study was to examine secular trends in body mass, body height and body mass index (BMI) from measured rather than self-reported values between 1972 and 2017. METHODS: A total of 4500 students (males = 51%) were selected from a stratified sampling. The age range varied between 6.0 and 17.9 years. The sample came from 24 elementary schools and 12 high schools located in six urban cities from the province of Québec. All the tests selected were based on standardized procedures that are recognized as valid and reliable. Standardization and modeling of smoothed percentile curves for each variable for both sexes were produced. RESULTS: Regional variations between youth from the province of Québec and those from all other Canadian provinces confirm the relevance of using data specific to the target population. Comparisons with the 1972 and 1982 data show an important increase in body mass (~ 7 kg, i.e. 16.4%) and BMI (~ 1.4 kg·m-2, i.e. 19.9%) with minor change in body height (~ 1.8 cm, i.e. 3.9%). Youth from low-income backgrounds (p = 0.001) as well as those living in large urban cities (p = 0.002) see their probability of developing overweight or obesity greatly increase (low-income = 2.1 times; large urban cities = 1.3 times). However, overweight and obesity rates seem to have stabilized at around 21% since 2004. CONCLUSION: This study provides up-to-date data on factors that contribute to the prevalence of overweight and obesity in youth in urban settings of Québec, and will be instrumental in guiding public health strategies designed to optimize growth outcomes.
RéSUMé: OBJECTIF: L'objectif principal de cette étude était d'examiner les tendances séculaires de la masse corporelle, de la taille et de l'indice de masse corporelle (IMC) de 1972 à 2017 à partir de valeurs mesurées plutôt que de valeurs autodéclarées. MéTHODE: Un total de 4 500 étudiants (garçons = 51 %) ont été sélectionnés à partir d'un échantillon stratifié. La fourchette d'âge variait entre 6,0 et 17,9 ans. L'échantillon provenait de 24 écoles primaires et 12 écoles secondaires situées dans six villes de la province de Québec (Canada). Tous les tests sélectionnés reposaient sur des procédures standardisées, reconnues comme valides et fidèles. Une standardisation et une modélisation des courbes centiles lissées ont été produites pour chaque variable pour les deux sexes. RéSULTATS: Les variations régionales entre les jeunes du Québec et ceux du reste du Canada confirment la pertinence d'utiliser des données spécifiques à la population cible. Les comparaisons entre les données de 1972 et de 1982 montrent une augmentation importante de la masse corporelle et de l'IMC (p ≤ 0,05) sans changement important de la taille corporelle. Les jeunes issus de milieux à faibles revenus (p = 0,001) ainsi que ceux vivant dans les grandes villes (p = 0,002) voient leurs risques de développer un surpoids ou de l'obésité augmenter considérablement (faibles revenus = 2,1 fois; grandes villes urbaines = 1,3 fois). Toutefois, les taux de surpoids et d'obésité semblent s'être stabilisés autour de 21 % depuis 2004. CONCLUSION: Cette étude fournit des données à jour sur les facteurs qui contribuent à la prévalence de l'embonpoint et de l'obésité chez les jeunes des milieux urbains du Québec et contribuera à orienter les stratégies de santé publique afin d'optimiser le suivi sur la croissance physique des jeunes.
Subject(s)
Body Height , Overweight , Male , Female , Adolescent , Child , Humans , Body Mass Index , Body Weight , Overweight/epidemiology , Quebec/epidemiology , Cross-Sectional Studies , Canada , Obesity/epidemiology , PrevalenceABSTRACT
Recent research has shown writing strategies to have a substantial impact on language learners' writing performance but little is known about what strategies EFL learners use and how they use them in writing academic texts such as reports, final assignments, and project papers. The study reported in this paper extends this line of research by investigating the strategies Vietnamese EFL pre-service teachers use in academic writing. Data included document analysis of 17 pre-service teachers' final assignment papers (one paper per teacher) and individual semi-structured interviews with ten teachers. The study adopted a content-based approach to qualitative data analysis with reference to a comprehensive research-based taxonomy for L2 academic writing strategies, including rhetorical, metacognitive, cognitive, and social affective strategies. The results show that rhetorical, metacognitive, and cognitive strategies were most frequently used by the teacher participants. The results further show that self-efficacy and self-regulation determined the teachers' use of strategies during the writing process. Implications for the L2 writing classroom focused on academic writing strategies to enhance pre-service teachers' writing quality will be discussed.
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The lack of specific on-ice tests to predict maximum lactate concentration limits the ability of coaches to better track and develop their ice hockey players. Thus, this study aimed to develop an equation for indirectly assessing the maximum lactate concentration produced from an all-out on-ice skating effort in elite adolescent ice hockey players. Twenty elite male ice hockey players participated in this study (age = 15.7 ± 1.0 year). The lactate anaerobic skating test (LAST) consisted of skating back and forth on an 18.2 m course at maximal speed with abrupt stops at each end for a total of 6 shuttles (total distance = 218.2 m; average time = 52.0 ± 2.0 s). The oxygen uptake was measured using a portable metabolic analyzer (Cosmed K4b2) and the maximum post-exercise lactate concentration with a Lactate Pro analyzer. The variables used to estimate lactate concentration were time, heart rate, number of skating strides in the last shuffle (6th) and the skating stride index. The average maximum lactate concentration was 14.4 mmol· L-1, which is expected in elite players. The analysis of explained common variance using T-test (r2 = 0.759) and linear regression (r2 = 0.863) demonstrates the validity of the model. Additionally, the root mean square error (RMSE = 0.60 mmol· L-1), the mean absolute error (MAE = 0.45mmol· L-1) and the standard error of estimate (SEE = 0.69 mmol· L-1) values further confirm the accuracy of the model. Thus, using simple and easy-to-measure variables (i.e., time and skating stride), coaches will be able to monitor more effectively their players' progress in an effort to optimize their individual on-ice performance.
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A gold nanoparticle-decorated graphene oxide (GO-AuNP) hybrid material was prepared by using the chemical reduction method. The obtained results showed that the AuNPs of about of 15 nm are well bound on the surface of GO. The GO-AuNP hybrid material was used for transparent conductive film (TCF) and organic/inorganic hybrid solar cells. The TCF based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) containing GO-AuNPs was fabricated at room temperature. The obtained results show that the TCF containing 0.5 wt% GO-AuNPs has a high transmittance of 69.7% at 550 nm, a low sheet resistance of 50.5 Ω â¡-1 and a conductivity that increased to 3960 S cm-1, which is three times higher than those of the PEDOT:PSS and PEDOT:PSS/GO film. The power conversion efficiency (PCE) of the n-Si/PEDOT:PSS hybrid solar cell containing GO-AuNPs was 8.39% and is higher than pristine PEDOT:PSS (5.81%) and PEDOT:PSS/GO (7.58%). This is a result of the increased electrical conductivity and localized surface plasmon resonance of the PEDOT:PSS coating layer containing the GO-AuNP hybrid material.
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Given the importance of ESP teaching, this study explores and compares students' and teachers' perceptions of effective ESP teaching. The researcher administered a 32-item Likert-scale questionnaire to 248 participants (216 students and 32 teachers) at five universities in Vietnam. The participants were then stratified to select 20 participants (fifteen students and five teachers) for interviews. Results showed that there were significant discrepancies between students and teachers' perceptions of four categories: task-based language teaching, corrective feedback and assessment, discipline specifications, and culture integration. However, students' and teachers' perceptions of three categories, namely language use, application of technologies, and grammar teaching, were aligned. Interview data generally confirmed the quantitative results and provided more insights into what the participants thought. It might be important for teachers to present their concerns about ESP teaching to students and understand students' needs and expectations to bridge the gaps.
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Fumigants are commonly used to control soil-borne pathogens of high-value crops, but they may also impact non-target soil microorganisms. Increasing interest in the use of sustainable management practices to control plant- and root-parasitic nematodes has resulted in the formulation of non-fumigant nematicides (chemicals or bionematicides) which are considered environmentally friendly alternatives to fumigants. However, the impact of these new products compared to standard fumigants on soil-borne pathogens, plant production, and the diversity and composition of non-target microbial communities in all crops remains unclear. To begin to address this knowledge gap, we examined the effect of fumigants commonly used in Florida (United States) strawberry production and newly formulated non-fumigant nematicides on nematode and weed control, plant growth, crop yield, and bacterial and fungal community diversity and predicted functionality. We found the standard fumigants increased crop yields and reduced weed pressure more than non-fumigants. Both fumigants and non-fumigants were an efficient management strategy to control sting nematodes. Treatments also impacted the abundance of specific beneficial and antagonistic taxa. Both fumigants and non-fumigants reduced soil bacterial and fungal diversity, an effect that remained for six months, thus suggesting a potential residual impact of these products on soil microorganisms. However, only fumigants altered soil microbial community composition and reduced network complexity, inducing a decrease or even a loss of some predicted bacterial and fungal functions, particularly during the first weeks after fumigation. Nevertheless, soil collected at the end of the season showed significant levels of root-knot nematode suppression in a growth chamber experiment, irrespective of the previous treatment. By linking the effect of fumigants and non-fumigants on soil-borne pests, plant and production, and the soil microbiome, this study increases our knowledge regarding the environmental impact of these products.
Subject(s)
Fragaria , Nematoda , Pesticides , Animals , Soil , Soil Microbiology , Weed Control , Antinematodal Agents , Bacteria , Crops, AgriculturalABSTRACT
Vietnam has undergone four waves of the Covid-19 pandemic in 2020 and 2021, which have posed significant market risks to various sectors. Understanding the market risk of Vietnamese sectors and its changes is important for policy implementation to support the economy after the pandemic. This study measures the sectoral market risks and examines the effects of the pandemic, policy responses and macroeconomic fundamentals on the market risks across sectors in Vietnam. We employ the Value-at-Risk (VaR) and Conditional Value-at-Risk (CVaR) techniques to measure the market risks for 24 sectors from 2012 to 2021. The market risk levels across Vietnamese sectors have changed significantly in response to the pandemic. Oil and Gas and Services sectors show the largest potential loss during the two Covid-19 waves in 2020. The Securities sector is the riskiest sector during the last two Covid-19 waves in 2021. Our results indicate that the new Covid-19 cases reported by the Government increase the market risk levels across Vietnamese sectors. On the other hand, enhancing containment and health policy and reducing economic policy uncertainty result in lower market risk across sectors. We also find that macroeconomic fundamentals such as the exchange rate and interest rate significantly affect the market risks across sectors in Vietnam.
Subject(s)
COVID-19 , COVID-19/epidemiology , Health Policy , Humans , Pandemics , Vietnam/epidemiologyABSTRACT
BACKGROUND: Double-cropping is a common practice in vegetable plasticulture whereby a second crop is planted on the same plastic bed as the first crop. Root-knot nematodes (Meloidogyne spp.) are one of the major soilborne constraints in double-cropped vegetables due to nematode population build-up on the first crop. We evaluated the effect of fumigant and non-fumigant nematicides applied on the first crop, on nematode infection and yield of the second crop in 10 field trials between 2017 and 2020. Fumigants were chloropicrin (Pic100), chloropicrin +1,3-D (PicClor60), and non-fumigant nematicides were oxamyl (Vydate), fluensulfone (Nimitz), fluopyram (Velum) and fluazaindolizine (Salibro). The first crop was tomato and double crops were cucumber, squash, zucchini, and cantaloupe. RESULTS: Fumigation with chloropicrin on the first crop increased root-knot nematode damage on the double-crop at the end of the season in seven trials, while the opposite was noted in one trial, and no difference was noted in two trials. Fumigation with chloropicrin+1,3-D resulted in root-knot nematode damage less than chloropicrin but more than non-fumigated plots. Cucurbit yield was greater in non-fumigated beds in four trials, and in chloropicrin-treated beds in two trials. Fluensulfone reduced root-knot nematode damage on the second crop in five out of 10 trials. CONCLUSION: Our results indicate that chloropicrin applied on the tomato crop may lead to increased root-knot nematode damage on the double crop. More research is needed to understand the processes behind this, but it is possibly related to a reduction in natural nematode soil suppressiveness due to the broad-spectrum fungicidal activity of chloropicrin. © 2022 Society of Chemical Industry.
Subject(s)
Hydrocarbons, Chlorinated , Pesticides , Solanum lycopersicum , Tylenchoidea , Animals , Antinematodal Agents/pharmacology , Fumigation , Hydrocarbons, Chlorinated/toxicity , Pesticides/pharmacologyABSTRACT
Herein, the effect of nanostructured silicon and gold nanoparticles (AuNPs) on the power conversion efficiency (PCE) of an n-type silicon/poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (n-Si/PEDOT:PSS) hybrid solar cell was investigated. The Si surface modified with different nanostructures including Si nanopyramids (SiNPs), Si nanoholes (SiNHs) and Si nanowires (SiNWs) was utilized to improve light trapping and photo-carrier collection. The highest power conversion efficiency (PCE) of 8.15% was obtained with the hybrid solar cell employing SiNWs, which is about 8%, 20% and 40% higher compared to the devices using SiNHs, SiNPs and planar Si, respectively. The enhancement is attributed to the low reflectance of the SiNW structures and large PEDOT:PSS/Si interfacial area. In addition, the influence of AuNPs on the hybrid solar cell's performance was examined. The PCE of the SiNW/PEDOT:PSS hybrid solar cell with 0.5 wt% AuNP is 8.89%, which is ca. 9% higher than that of the device without AuNPs (8.15%). This is attributed to the increase in the electrical conductivity and localized surface plasmon resonance of the AuNP-incorporated PEDOT:PSS coating layer.
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Background: In the context of concerns regarding the cardiorespiratory fitness (CRF) of youth populations, the aims of this study were: (1) to update reference values for the VO2max for school-aged Canadians and (2) to document secular trends in CRF after a 35-year interval. Methods: Between September 2014 and April 2017, the CRF of 3725 students (53.2% boys; 6.0 to 17.9 yrs) was determined using the 20-m shuttle run test. The sample was collected in 36 different schools from six cities of Québec (Canada). Results: Median values of VO2max decreased with age in both sexes (p ≤ 0.05). By the age of 10, more than 20% of boys showed VO2max values below the recommended value (42 ml·kg-1·min-1). At the age of 17, that proportion reached 56.8%. A similar proportion of 12 yrs girls (20%) were under the recommended minimal value (37 ml·kg-1·min-1) and that value reached 69.9% at the age of 17. Compared to 1982, the VO2max at age 17 has declined by 18% for boys and 12% for girls. The situation is worse in terms of functional capacity (number of stages completed) with an overall decrease of more than 30%. Conclusion: This study demonstrates that, compared to data obtained using the same methodology 35 years ago, the CRF and functional capacity of children and adolescents has declined to levels that should raise concerns from a public health perspective. Thus, the development of strategies to promote a physically active lifestyle in youth is more relevant than ever.
Subject(s)
Cardiorespiratory Fitness , Male , Female , Humans , Adolescent , Child , Canada , Electrocardiography , Cities , Reference ValuesABSTRACT
Among 200 fungal strains isolated from the soil, only one culture filtrate of Aspergillus flavus JCK-4087 showed strong nematicidal activity against Meloidogyne incognita. The nematicidal metabolite isolated from the culture filtrate of JCK-4087 was identified as cyclopiazonic acid (CPA). Because JCK-4087 also produced aflatoxins, six strains of Penicillium commune, which have been reported to be CPA producers, were obtained from the bank and then tested for their CPA productivity. CPA was isolated from the culture filtrate of P. commune KACC 45973. CPA killed the second-stage juveniles of M. incognita, M. hapla, and M. arearia with EC50-3 days 4.50, 18.82, and 60.51 µg mL-1, respectively. CPA also significantly inhibited egg hatch of M. incognita and M. hapla after a total of 28 days of treatment with the concentrations > 25 µg mL-1. The enhancement of CPA production by P. commune KACC 45973 was explored using an optimized medium based on Plackett-Burman design (PBD) and central composite design (CCD). The highest CPA production (381.48 µg mL-1) was obtained from the optimized medium, exhibiting an increase of 7.88 times when compared with that from potato dextrose broth culture. Application of the wettable power-type formulation of the ethyl acetate extract of the culture filtrate of KACC 45973 reduced gall formation and nematode populations in tomato roots and soils under greenhouse conditions. These results suggest that CPA produced by P. commune KACC 45973 can be used as either a biochemical nematicide or a lead molecule for developing chemical nematicides to control root-knot nematodes.
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Thai basil (Ocimum basilicum var. thyrsiflora) is an important ethnic aromatic herb native to Southeast Asia. According to the Vegetable Production Handbook of Florida 2020-2021, Asian vegetables are currently grown on more than 4,000 ha in Florida, and Thai basil is one of the most commonly grown among these. Meloidogyne spp. cause severe damage to different basil cultivars (Brito et al. 2007). During May-July 2020, plant stunting and galled root symptoms were observed on Thai basil plants sampled from a commercial Asian vegetable farm in Wimauma, Florida (27°44.951' N; 82°16.271' E); 1,972 root-knot nematode second-stage juveniles (J2s) were extracted from 200 cm3 soil. A pathogenicity test was performed in September 2020 at the University of Florida Gulf Coast Research and Education Center, Wimauma, Florida. Ten of 20, three-week-old nematode-free Thai basil plants were inoculated with 5,000 eggs of field nematode cultures. Two months after inoculation (temperature = 22.8 ± 3.8 °C, relative humidity = 85.6 ± 14.0 %), average gall index (Bridge and Page 1980) = 5.4 ± 1.1 were only observed in inoculated plants, and 69,276 ± 18,904 eggs were extracted from roots using the NaClO method (Hussey and Barker 1973); 5 ± 7 J2s / 200 cc soil were recovered by the modified Baermann funnel technique (Forge and Kimpinski 2007). Nematode reproduction factor (RF) = 13.86 ± 3.78 (Nicol et al. 2010). Morphological measurements (mean, standard deviation and range) of J2s (n=20) included body length = 394.0 ± 22.3 (362.8 - 437.9) µm, body width = 15.7 ± 1.2 (13.6 - 18.3) µm, and stylet length = 12.8 ± 1.1 (10.4-14.5) µm. The perineal pattern of matured female (n=5) was oval-shaped with coarse and smooth striate; the dorsal arch was high and round; no lateral line presented. Morphological characteristics of females and J2s were consistent with those described for M. enterolobii (Yang and Eisenback 1983). DNA was extracted from a single female picked from infected Thai basil root using NaOH digestion method (Hübschen et al. 2004). The D2-D3 expansion segment of 28S rDNA and the COXII region on mitochondrial DNA were amplified by PCR using the primers 28S391a/28S501 and C2F3/1108 (Ye et al. 2020); the species was also confirmed with species-specific primers Me-F/Me-R (Ye et al. 2020). PCR products were sequenced by the Genomic Sciences Laboratory (North Carolina State University, Raleigh, NC, USA) and the results were recorded in the NCBI with GeneBank Accession Nos. MW488150 and MW507374. The sequences showed 100% identity with M. enterolobii in D2/D3 (KP901079, KP411230) and COXII (MN809527, KX214350). M. enterolobii (M. mayaguensis) has been reported on sweet basil in Florida (Brito et al. 2008). To our knowledge, this is the first detection of M. enterolobii on Thai basil in Hillsborough County, Florida. It is not clear to what extent M. enterolobii reduces the yield of Thai basil, but the RF value obtained in the pathogenicity test indicates the crop is certainly a very good host. Limited information is available on the distribution of M. enterolobii in Florida and the US. M. enterolobii is known to break down the root-knot resistance of crops including soybean, sweet potatoes, and tomatoes (Philbrick et al. 2020). This nematode is considered one of the major emerging threats to agriculture in the southeastern US. A multistate research and outreach program (FINDMe program) was initiated in 2019 to study the distribution and management of this nematode in the southeastern US.
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Soil fumigation remains the standard practice to manage soilborne pathogens such as plant-parasitic nematodes, bacteria, and fungi, especially in high-value crops. However, increasing regulatory pressure due to the inherent and broad-spectrum toxicity and negative environmental impact of chemical soil fumigants, its negative effect on overall soil health, and increasing demand for organic produce, has created a growing interest in biological fumigants. Many plants and microorganisms emit volatile compounds, which can potentially be used as bio-fumigants. In this mini-review, we summarize the current status of nematology studies focused on the development of volatile compounds emitted from plants and microorganisms as fumigants to control plant-parasitic nematodes. The gap of knowledge and challenges of studying volatile compounds are also addressed.
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BACKGROUND: Biotic and abiotic factors such as microbes and soil temperature can affect nematicide efficacy. Two experiments were conducted to test the effect of three soil temperatures on the efficacy of nonfumigant nematicides (fluopyram, fluensulfone, oxamyl and fluazaindolizine) against Meloidogyne javanica in pasteurized and natural soil in planta. RESULTS: The results showed that all tested nematicides were more efficacious in pasteurized than in natural soil. Temperature affected the nematicides differently with no effect of soil temperature on oxamyl and fluazaindolizine, whereas fluopyram and fluensulfone had greater efficacy at higher soil temperatures. CONCLUSION: Temperature effects were noted for some but not all nonfumigant nematicides. Fluopyram and fluensulfone were less effective when applied in cold soil, whereas oxamyl and fluazaindolizine were not affected by soil temperature. Although all nematicides resulted in almost complete control of M. javanica in pasteurized soil, this was not the case in natural soil, and much more root damage and nematode reproduction was noted in the latter. © 2021 Society of Chemical Industry.