Development Of Best Management Practices Research Articles

First report of Rhizoctonia solani AG-2-2 IIIB causing Rice sheath blight in China.

Rice (Oryza sativa) is an important crop worldwide, rice is susceptible to many pathogens, one of the most significant being Rice Sheath Blight, caused by Rhizoctonia solani. This disease initially produces cloudy spots on the leaf sheaths and later affects grain filling, resulting in yield losses of over 45%（Chen et al. 2013） when severe. In many southern rice-growing areas of China, the impact of this disease has risen to become the most damaging of the three major rice diseases (Margani et al. 2018). In July 2023, In Yongfu County, Guangxi (110.022°E, 25.010°N), symptoms of rice sheath blight were observed. The leaf sheaths were affected, with small, water-soaked, dark green spots with indistinct edges appearing near the water surface. These spots gradually expanded into elliptical or cloud-like lesions. Eventually, the center of the lesions turned straw-yellow to grayish-white, while the edges turned brown to dark brown. Often, several lesions merged into large cloud-like patches. Fifteen symptomatic sheaths were collected disinfecting pieces of necrotic tissue with 3% NaClO for 1.5 minutes, followed by 75% alcohol for 1 minute. The pieces were then rinsed with sterile distilled water, subsequently plated on Potato Dextrose Agar in Petri dishes, and incubated at 28°C in the dark. One isolate was obtained from each diseased plant using the hyphal tip method. (Feng et al. 2008). Isolates were obtained and displayed initially white mycelium and gradually turned brown after three to four days. Septate hyphae were 4.27 to 10.73 μ m (average 6.41 μ m) in diameter and branched at Right angle or acute angle with a constriction at the origin of the branch point. Staining with 1% safranin O and 3% KOH solution (Bandoni 1979) revealed multinucleated cells (three to nine nuclei per cell, n = 144). In summary, these characteristics were consistent with the description of Rhizoctonia solani Kühn (Meyer et al. 1990). The anastomosis group (AG) was confirmed by selecting three representative isolates (GL-Q-10, GL-Q-13, GL-Q-15) for molecular identification. The target DNA was extracted using Chelex-100. The internal transcribed spacer (ITS) region was amplified and sequenced with primers ITS1 and ITS4. The sequences were deposited in GenBank (ITS, PQ047154, PQ047150, and PQ047151 The base pairs are respectively 713bp, 715bp and 776bp, respectively). Upon searching GenBank, accession number MT385836 was found (Zhou et al. 2021), which has a similarity of 99.15% with PQ047154, 98.87% with PQ047150, and 99.30% with PQ047151. Phylogenetic tree analysis based on ITS sequences showed that the isolates clustered monophyletically with strains of R. solani AG-2-2 IIIB. The fusion group of the strain is verified by the shape and color of its mycelial growth on PDA at 35°C, enabling the distinct differentiation of AG-2-2 IIIB from AG-2-2 IV in terms of both morphology and coloration.（Aktaruzzaman et al. 2019） Pathogenicity tests involved culturing the pathogenic bacteria on PDA for 7-10 days, Then, 10 healthy rice plants (greenhouse potted rice variety Dian Heyou 615) were selected at the heading stage, and 5 plants were inoculated on the leaf sheaths with 5 strains of 5 mm fungus cake with pathogenic bacteria and 5 plants without pathogenic bacteria (The rice soil was disinfected), wrapped in cotton for moisture retention. All plants were sealed in transparent plastic bags and incubated in a greenhouse at 30 °C for 7-15 days, with daily moisturizing using sterile distilled water (Humidity control at 70%). Seven days postinoculation, Those containing pathogenic bacteria have symptoms of rice sheath blight, No symptoms were detected on control plants. Rhizoctonia solani AG-2-2 IIIB was re-isolated from the inoculated plants as previously described, thus fulfilling Koch's postulates. The pathogenicity tests were repeated three times. At present, Rhizoctonia solani AG-2-2 IIIB is primarily pathogenic in plants such as sugar beet and beans. It has only been reported in Japan and other countries to cause rice disease (Engelkes et al. 1996; Kenji Inagaki et al. 2004), and Rhizoctonia solani AG-2-2 IIIB has never been reported in China to cause disease in rice. To our knowledge, this study is the first to identify Rhizoctonia solani AG-2-2 IIIB causing rice sheath blight in China. This finding will aid further research on rice sheath blight defense strategies and contribute to the development of better management practices for this disease.

Ecological inferences in Orchidaceae species from the Brazilian subtropical Atlantic Forest based on morphological and functional anatomical traits

Ecological anatomy studies seek to link structural aspects to environmental pressures, improving knowledge about the occurrence and distribution of species. Orchidaceae is a group with high species richness and ecological diversity, well represented in the Brazilian Atlantic Forest, a biodiversity hotspot. The Iguaçu National Park (ParNa Iguaçu) is an important remnant of the southern Brazilian Atlantic Forest with a high richness of Orchidaceae. Given the family's diversity and the relevance of ecological anatomy studies for interpreting traits associated with the survival of plants in certain environments, we studied 38 species of Orchidaceae from ParNa Iguaçu, seeking to identify possible functional groups. For this, we surveyed 57 leaf morpho-anatomical characters and conducted histochemical and statistical tests. The morpho-anatomical traits group the species into two functional groups, with Cyclopogon congestus emerging isolated. In group A, xeromorphic morphoanatomical characters predominate, and group B combines members with meso/hygromorphic characteristics. We advocate the importance of understanding the ecological behavior of species, especially Orchidaceae, due to their important ecological role, in conservation actions in protected areas. Furthermore, our results highlight the morphological and anatomical diversity of the Orchidaceae found in ParNa Iguaçu, as well contributing to the development of better management practices for these plants, considering the threats posed by the opening of clearings and climate change.

Prioritisation of quarantine pest list for the Caribbean using a multi-criteria decision approach

Quarantine plant pests are socially, economically and environmentally important due to their impact on food security, human health, global trade and crop production costs. The increase in global trade and tourism, frequent occurrence of natural disasters and climate changes have exacerbated the rate of entry, establishment and spread of plant pests regionally and globally. It has, therefore, become exigent to develop a list of pests of quarantine importance at the regional and national levels to prioritise and allocate the limited available resources to manage the associated risks. In the present study, the Technical Committee on the Formulation and Prioritisation of a Regional Priority Pest List for the Caribbean, in collaboration with the National Plant Protection Organisation of the Caribbean countries and the United States Department of Agriculture - Animal and Plant Health Inspection Service (USDA-APHIS), developed and prioritised a quarantine pest list using a multi-criteria decision-making approach. The technical committee successfully evolved the process in 2014 and 2018 and developed a list of the top 10 pests of quarantine importance for the Caribbean Region, employing the Delphi Technique (DT) and Analytical Hierarchy Process (AHP) through the assignment of criteria that are relevant to the region. The Mediterranean fruit fly (Ceratitis capitata), frosty pod rot (Moniliophthora roreri) and the tomato leaf miner (Tuta absoluta), listed as top quarantine pest threats, were subsequently detected in the region. This exercise guided the authorities in advance to allocate resources and to develop response plans including capacity building for surveillance and detection of priority pests. This has demonstrated the significance and appropriateness of the multi-criteria decision approach to determine priority pest lists and prepare the region for development of better management practices.

First report of Watermelon crinkle leaf‐associated virus 1 (WCLaV‐1) on Cucurbita pepo in the United States

Zucchini (Cucurbita pepo) is widely grown in Florida and contributes to the US$35 million value production of all types of squash in the state (United States Department of Agriculture/ National Agricultural Statistics Service, 2021). In August 2022, zucchini (cv. Renegade) in a commercial field in North Florida, USA, showed pronounced chlorosis and mild crinkle on leaves in scattered areas (Fig. 1). The disease incidence was approximately 35%. One diseased leaf from each of six zucchini plants were collected randomly for diagnosis; three from 21-day-old plants (noted as Z272), and three from 28-day-old plants (noted as Z273). All samples tested negative for Cucumber mosaic virus, Squash mosaic virus and Zucchini yellow mosaic virus using ImmunoStrips (Agdia, USA). Subsequently, total plant RNA was extracted using a Quick-RNA MiniPrep kit (Zymo Research, USA). A conventional one-step RT-PCR (New England Biolabs, USA) was used to test the samples using primer pairs for Cucurbit chlorotic yellows virus (CCYV; Jailani et al., 2022), Watermelon crinkle leaf-associated virus 1 and 2 (WCLaV-1 and WCLaV-2; genus Coguvirus) (Hernandez et al., 2021) and Watermelon mosaic virus 2 (WMV-2; 5′-AAAGCTCCATACATAGCTGAGAC-3′/ 5′-CGGCCTTCATTTGTGCTATTG-3′). The samples were negative for CCYV, WMV-2 and WCLaV-2, but positive for WCLaV-1 using specific primers for the RNA-dependent RNA polymerase (RdRP) region on RNA-1 (Table 1). To confirm the detection of WCLaV-1, specific RNA-2 primers, targeting the coding regions of movement protein (MP) and nucleocapsid protein (NP), respectively, were used in an RT-PCR assay (Table 1, Hernandez et al., 2021). The sequences of the RdRP amplicon (881 bp) (GenBank Accession No. OP484885) had 99% nucleotide identity with WCLaV-1 isolates from China (KY781184) and the USA (OL469153 and OL469154). The sequences of the MP amplicon (538 bp) (OP484884) shared 99% nt identity with Australian WCLaV-1 isolate S6 (ON934517) and American isolates “Turner” and “Wilcox-02” (OM751929 and OM751928). The NP amplicon sequences (786 bp) (OP484883) shared 99% nt identity with Chinese isolate KF-1 (KY781186) and American isolate Wig-WM-D10 (MW559081). Both the samples (Z272 and Z273) had similar results, therefore only sequences from sample Z272 were submitted to GenBank. The results were further confirmed by SYBR®-based real-time RT-PCR using the WCLaV-1 MP gene-specific primer pairs (WCLaV-1FP/WCLaV-1RP) (Adeleke et al., 2022). WCLaV-1 and WCLaV-2 were first reported in watermelon in China (Xin et al., 2017), followed by America (Hernandez et al., 2021), Brazil (Maeda et al., 2022) and Australia (Mulholland et al., 2023). To our knowledge, this is the first report of WCLaV-1 on zucchini in America and globally. The mode of transmission of the virus in currently unknown. Studies to understand the potential of vector and seed transmission should be conducted to aid the development of best management practices. In the meantime, growers will have to rely on keeping pests of zucchini crop under control, practicing tillage of plant residues, and removing weeds routinely as general good practices.

Temperature-associated virulence, species susceptibility and interspecies transmission of a Lactococcus petauri strain from rainbow trout.

Lactococcus petauri is an important emergent aquaculture pathogen in the USA. To better understand environmental conditions conducive to piscine lactococcosis and the susceptibility of fish species, laboratory-controlled challenges were used as models of infection. Rainbow trout Oncorhynchus mykiss maintained at 13 or 18°C were challenged by intracoelomic (ICe) injection with 101, 103 or 105 colony-forming units per fish (CFU fish-1) and monitored for 21 d. At 13°C, trout experienced mortalities of 7, 7 and 0%, and bacterial persistence of 0, 20 and 0% in survivors, respectively. When exposed to the same bacterial doses, trout maintained at 18°C experienced mortalities of 59, 84 and 91%, and bacterial persistence of 60, 66 and 0% in survivors, confirming a significant role of temperature in the pathogenesis of lactococcosis. Additionally, the susceptibility of rainbow trout, Chinook salmon Oncorhynchus tshawytscha, white sturgeon Acipenser transmontanus, Nile tilapia Oreochromis niloticus, and koi Cyprinus carpio to infection by L. petauri was compared using ICe challenges at 18°C. Trout and salmon experienced 96 and 56% cumulative mortality, respectively, and 17% of surviving salmon remained persistently infected. There were no mortalities in the other fish species, and no culturable bacteria recovered at the end of the challenge. However, when surviving fish were used in further cohabitation trials, naïve trout housed with previously exposed tilapia exhibited 6% mortality, demonstrating that non-salmonids can become sub-clinical carriers of this pathogen. The data obtained provide useful information regarding temperature-associated virulence, fish species susceptibility, and potential carrier transmission of L. petauri that can be used in the development of better management practices to protect against piscine lactococcosis.

Spatiotemporal Dynamics of Carbon Footprint of Main Crop Production in China.

As a major agricultural country, the comprehensive accounting of the dynamics and composition of the carbon footprint of major crops in China will provide a decision-making basis for environmental management and agricultural green development in the whole process of the major crop production system in China. To investigate the spatiotemporal dynamics of the carbon footprint for major crops in China, a life cycle-based carbon footprint approach was used to evaluate the carbon footprint per unit area (CFA) and per unit yield (CFY) of eight crops for the period of 1990 to 2019. Our results showed that the CFA for all major crops showed an increasing trend with time before 2016 but slowly decreased afterward, while the CFY decreased by 16-43% over the past 30 years due to the increase in crop yield. The three main grain crops, rice (4871 ± 418 kg CO2-eq · ha-1), wheat (2766 ± 552 kg CO2-eq · ha-1), and maize (2439 ± 530 kg CO2-eq · ha-1), showed the highest carbon footprint and contribution to the total greenhouse gas (GHG) emissions, mainly due to their larger cultivated areas and higher fertilizer application rates. CH4 emission was the major component of the carbon footprint for rice production, accounting for 66% and 48% of the CFA and CFY, respectively, while fertilizer production and usage were the largest components of carbon footprint for dryland crops, making up to 26-49% of the CFA and 26-50% of the CFY for different crops. The present study also highlighted the spatial and temporal patterns of the carbon footprint for major crops in China, which could serve as references for the development of best management practices for different crop production in China, to mitigate agricultural GHG emission and to pursue low-carbon agriculture.

Soil Enzyme Activity Behavior after Urea Nitrogen Application.

Understanding how fertilizer application (particularly N, the most used chemical fertilizer worldwide) interacts with soil microbes is important for the development of best management practices that target improved microbial activity to enhance sustainable food production. This study was conducted to determine whether urea N rate and time of application to maize (Zea mays) influenced soil enzyme activity. Enzyme activity was determined by monitoring fluorescein diacetate (FDA) hydrolysis, ß-glucosidase, acid-phosphomonoesterase, and arylsulfatase activities. Experiments were conducted from 2014 through 2016 to compare single (fall or spring applications) and split applications of N at varying N rates under irrigation (Becker) and rainfed conditions (Lamberton and Waseca) in MN, USA. Nitrogen rates varied by location and were based on University of Minnesota guidelines. Soil samples were collected seven times each season. Nitrogen application split into two applications increased FDA activity by 10% compared with fall and spring applied N at Waseca. Fall or spring N application decreased arylsulfatase activity by 19% at Becker and by between 13% and 16% at Lamberton. ß-Glucosidase and acid-phosphomonoesterase activities were unaffected by N application. Sampling time and year had the greatest impact on enzyme activity, but the results varied by location. A negative linear relationship occurred between FDA and ß-glucosidase activity at all three sites. In summary, urea N application had small effects on enzyme activity at the sites studied, suggesting that some form of organic N could be more important than the ammonium provided by urea.

Estimation and Impact Factor of Pathogens in the Lijiang River Using Water Quality Modeling

The pathogen plays an important role in spreading infection and bad impact on the public health of the river. Therefore, water quality as a model is used to simulate the spreading and fate of the pathogen in Lijiang River, it is located in Lijiang City, Yunnan Province, China (100°25'E, 26°86'N). Even at low bacterial levels, there is a risk of pathogens in the Lijiang River ecosystem. The water quality model results showed that the spatiotemporal (space and time) migration of pathogenic bacteria in Lijiang River from 2005 to 2015 was quantitatively revealed by the model simulation. The simulation results also showed that the transports of pathogenic bacteria in Lijiang River are extremely sensitive to the speed distribution and seasonal temperature characteristics. The study found that the rising water temperature in spring leads to a sharp rise in the concentration of pathogenic bacteria. When the water temperature is low in winter, the simulated pathogenic bacteria are relatively stable, which is lower than the concentration of pathogenic bacteria at high temperature. If the spring water temperature rises, the flow rate increases, the concentration of pathogenic bacteria accordingly increases. This research recommends the development of best management practices to control microbial growth in river basins.

Physiological analysis of growth and development of winter carinata (Brassica carinata A. Braun)

AbstractBrassica carinata is a non‐food, low‐carbon, none‐to‐low indirect land‐use change impact oilseed feedstock grown for sustainable biofuels, bioproducts, and high protein seed meal. Understanding carinata growth and development is critical to the development of best management practices for maximum productivity and profitability of double‐cropped farming systems. Field experiments were conducted during 2017–2018 (Year 1) and 2018–2019 (Year 2) winter–spring growing seasons in Quincy, Florida, to quantify the total aboveground dry matter accumulation (TDM), allocation, growth, nutrient uptake, and seed quality. The two carinata cultivars Avanza 641 and AX17012 accumulated 10826 and 9343 kg TDM ha−1 in Year 1 and 9655 and 10,642 kg TDM ha−1 in Year 2, respectively, at harvest maturity. The proportion of DM in the vegetative parts such as leaves and stems decreased, and the DM in reproductive structures such as silique walls and seeds increased with maturity. Seed yield (SY) was similar between cultivars but differed between years with Year 1 (2732 kg ha−1), producing 29% greater SY than Year 2 (1929 kg ha−1). Carinata primary stem has 17–20 leaf nodes, with 75%–88% of the axillary meristems producing primary and secondary branches. Crop growth rate (CGR) increased from vegetative to pod development for both cultivars in Year 1, while in Year 2, AX17012 and Avanza 641 attained maximum CGR at the pod development and bolting/flowering stages, respectively. Maximum seasonal nutrient uptake in leaves, stems, and siliques generally occurred in the early, mid, and late season, respectively, in both years. Seed weight, oil, monounsaturated fatty acids, C18:3, C20:1, and C22:1 concentrations increased with plant age, whereas protein, glucosinolate, polyunsaturated fatty acids, saturated fatty acids, C18:1, and C18:2 concentrations decreased with plant maturity. These results can be used for crop modeling to predict growth, development, and yield and aid in developing in‐season decision support tools.

Aggregate and Agriculture: Cultivating Neighbourly Relations, Stories from Across Ontario

Aggregate extraction and agriculture are prominent land uses in rural southern Ontario, and both industries are vital contributors to the provincial economy. However, these industries compete for the same land base and their operations have the potential to negatively impact the other. There is currently little research into this relationship, particularly at the site or neighbour scale. This project, in its third year, is designed to address this gap and to provide best management practices to both agricultural and aggregate operators, as well as local and provincial governments, about how these industries can better work together. While research has been conducted regarding the social impacts of aggregate extraction on rural residents, little is known regarding the social, economic, environmental and land use impacts on farms operating in close proximity to aggregate extraction activity. The aggregate industry is widely believed to cause a variety of undesirable impacts, including noise, dust, road traffic, extended hours of operation, as well as a loss of water quantity and quality. The development of best management practices is important to help mitigate these potential impacts, both at the local level and for rural communities at large. This presentation provides a summary of research to date as well a preliminary analysis of more than 150 farm surveys collected over the last year. Next steps include further consultation with aggregate operators and more in-depth interviews with key informants from both industries.

Multiagency Collaboration Strengthens Applied Research and Mitigation of Phytophthora ramorum at a Botanical Garden in Washington State

Phytophthora species pose significant challenges to public gardens, but collaboration can help contaminated gardens minimize their impacts and remain open to the public. Phytophthora ramorum was detected at the Bloedel Reserve—a botanical garden in Washington State—in 2015 but has not been recovered from surveys of plant material since 2016 following coordinated regulatory responses, research activities, and adaptative management decisions. Here we summarize efforts that were made to reduce the impact of P. ramorum on the Bloedel Reserve and limit the spread of this pathogen to nearby landscapes. Regulatory responses included detection and removal of positive plants, soil steaming, and the development of best management practices in the Reserve. Measures to adapt management in the garden included supporting applied research, removal of host plants, fungicide sprays, trail maintenance, and signage. The garden also featured P. ramorum in their education and outreach programs and used this as an opportunity to teach the public about invasive species.

Role of Horses as Potential Vectors of Non-Native Plant Invasion: An Overview

Non-native plant invasions can lead to staggering ecological and economic costs. Thus, land managers are concerned about vectors of seed and propagule introduction onto public lands. Because horses are one of several potential vectors of non-native seed dispersal, we summarize and interpret existing literature and identify potential impacts of horse use on non-native plant spread in natural areas. Several studies indicate non-native seeds can germinate after digestion by horses. In addition to their ability to carry viable non-native seeds in their feces, the literature indicates horses can trample native vegetation, cause soil disturbance, and increase soil nitrogen availability in some habitats. The combination of disturbance, which is known to increase invasibility, and introduction of seeds in horse feces could promote non-native plant invasions in wildlands. However, in situ studies have not demonstrated direct causal links between horses and plant invasions. More research is required to determine where, and to what extent, establishment and spread of non-natives occurs in situ as a direct result of disturbances and seed introduction by horses. Guidelines or regulations regarding horse use already exist in some recreational areas. Where none exist, we recommend development of best management practices, such as weed education programs for equestrians, use of Certified Weed Free Feed, and placement of manure bunkers at horse camps and trailheads.Lauren D. Quinn, Adda Quinn, Mietek Kolipinski, Bonnie Davis, Connie Berto, Mark Orcholski, and Sibdas Ghosh. 2010. “Role of Horses as Potential Vectors of Non-Native Plant Invasion: An Overview.” Natural Areas Journal 30(4):408-416

Understanding dissolved oxygen concentrations in a discontinuously perennial stream within a managed forest

The concentration of oxygen dissolved in water affects aquatic organisms. Unrestrained logging and site preparation can depress dissolved oxygen (DO) concentrations in adjacent streams by elevating temperatures (with removal of riparian shade), impounding channels (reduced reaeration rates), and introducing fresh, oxygen-depleting slash. One of the first paired watershed studies investigating the use of streamside management zones, the Alsea Watershed Study (AWS) in coastal Oregon (1958–1973), highlighted the potential to depress DO concentrations in streams adjacent to harvest units. This and other studies spurred development of Best Management Practices (BMPs) and forest practice rules to maintain, among other things, favorable DO concentrations in streams. A new study of the Alsea watersheds (2006–2015) found little signal of management effects on DO concentrations. It did find that a discontinuously perennial stream (where reaches go subsurface during low flows) can experience naturally low DO concentrations. Forest managers can avoid exacerbating low DO conditions using simple BMPs, but discontinuously perennial forest streams are predisposed to low DO concentrations.

Alkaline hydrolyzable nitrogen and properties that dictate its distribution in paddy soil profiles

Nitrogen (N) is a key nutrient for rice production, and its bioavailability in paddy soils is strongly coupled to soil organic matter (SOM) cycling. A better understanding of potentially available N forms in soil, such as alkaline hydrolyzable N (AH-N), and their depth distribution will support the development of best management practices to improve the N use efficiency of rice while minimizing adverse environmental effects. Fifteen rice (Oryza sativa L.) fields from Southern Brazil were selected, and stratified soil samples were taken to a depth of 60 cm before crop establishment. Selected soil physical and chemical properties were analyzed to evaluate their relationships with AH-N contents in the soil profile. The AH-N contents below 20 cm varied extensively (increased, reduced, or constant) compared with that above 20 cm. Although clay and clay + silt contents were highly correlated to AH-N for some soils, the major property dictating AH-N distribution by depth was total N (TN), as the correlation between TN and AH-N was mainly by direct effect. The proportion of TN recovered as AH-N across sites and depths presented high amplitude, and thus AH-N was not a constant N pool across depths, indicating that AH-N can be affected by soil management practices even when TN showed no major changes. The distinct distribution of AH-N across soil sampling sites and depths indicates that depths greater than 20 cm should be considered when calibrating the AH-N index for N fertilizer recommendations for flooded rice in Southern Brazil.

Assessment of water quality conditions in the Upper Johor River Basin

The water quality data from 2 sampling stations in the Upper Johor River Basin (Upper Johor River and Sayong River) were analysed to evaluate the water quality conditions. The variation in water quality parameters between base and storm flow events were compared to identify the pollutant sources. The results indicated that Biochemical Oxygen Demand (BOD) was the main cause for non-point source pollution of the study area. The overall water quality conditions were good in terms of dissolved oxygen and total nutrients (Nitrogen and Phosphorus). The dominant sources of BOD could be from the fertiliser timing and application. Different from BOD, the majority of the water quality samples were from baseflow events for dissolved oxygen, total nitrogen and total phosphorus. The major differences between four water quality parameters are failing septic system, oil palm mills, wastewater treatment plants and domestic waste. The results from this research would provide useful information for total maximum daily load calculation, establishment of watershed and nutrient model, and development of Best Management Practices for the Upper Johor River Basin and comparable study area.

Evolution of the relationship between total suspended solids concentration and turbidity during flushing sequences of water pipes

Abstract Particle accumulation and circulation in water distribution systems are significant in the development of good management practices to protect against discoloration events, which are a major cause of water customer complaints. Quantifying the amount of particles deposited in water pipes is usually done by obtaining total suspended solid measurements while performing flushing sequences, which requires time, skills, and equipment. Some authors explored the possibility of rapidly approximating total suspended solids concentration (TSSC) in water pipes by measuring water turbidity on site, but they obtained different results and coefficients of correlation. This paper presents the results of tests performed in the laboratory on a test loop. Unidirectional flushing (UDF) and air scouring sequences were performed under various hydraulic conditions and two different particle origins. Samples were obtained along each sequence, and the turbidity and TSSC were measured. The results illustrate that the ratio between turbidity and TSSC may vary greatly between samples, up to 10 times during UDF sequences and 20 times during air scouring sequences. Particle origin, flushing method, and sampling time are all factors impacting the turbidity/TSSC ratio. This is why TSSC should not be estimated from a single turbidity reading.

First Report of Black Currant Reversion Virus and Gooseberry Vein Banding Associated Virus in Currants in Bosnia and Herzegovina

Currants (Ribes spp.) are infected by at least 30 viruses (Koloniuk et al. 2018; Teifion Jones 2002), yet two are associated with the most important virus diseases of the crop: black currant reversion virus (BRV) for currant reversion and gooseberry vein banding associated virus (GVBaV) for the homonymous disease (Teifion Jones et al. 2001). BRV belongs to subgroup C of the genus Nepovirus of the family Comoviridae, whereas GVBaV is a member of genus Badnavirus, family Caulimoviridae (Petrzik et al. 2012). To this date, there is no information on the presence of either viruses in currant in Bosnia and Herzegovina (BiH). Surveys were carried out to assess the occurrence and diversity of the two viruses using high-throughput sequencing (HTS). Thirteen currant specimens (one red, one white, and 11 black) were collected in spring 2018 from commercial orchards in three localities (Travnik, Teslic, and Bugojno). Only three plants exhibited virus-like symptoms: the red currant (Ribes rubrum) from Travnik displayed leaf and flower malformation; the white currant and one black currant (R. nigrum) from Teslic showed yellow patterns and chlorosis on the upper canopy. RNA was extracted from seven samples (white, red, and black currants; both symptomatic and asymptomatic) using the Spectrum Plant Total RNA Kit (Sigma-Aldrich, Germany) and further depleted of ribosomal RNA using the KAPA RNA Hyper+RiboErase HMR kit. Libraries were generated and sequenced on the Illumina NextSeq 500/550 platform in separate reactions. Sequence analysis using Virfind (Ho and Tzanetakis 2014) revealed the presence of BRV in the red currant plant with typical disease symptoms and an asymptomatic black currant (47 and 28 contigs respectively, from 105 to 1,584 bp) and GVBaV in an asymptomatic plant (17 contigs from 350 to 1,903 bp). Nucleic acids were extracted from all 13 samples using the Poudel et al. (2013) protocol that facilitated detection of both DNA and RNA viruses. Reverse transcription PCR (RT-PCR) and PCR analyses were performed with two pairs of virus-specific primers for BRV (F, 5′-GTAATACGCTGGTGTCTC-3′/R, 5′-GAAAGGACATTTCAGACTC-3′ and F, 5′-ATTTCGAGCTGTATGGTCG-3′/R, 5′-CTCGGAAGCAGTAGACCT-3′ [Lemmetty et al. 2001]) and for GVBaV (F, 5′-ACATCAAAGGGAAGGACAAC-3′/R, 5′-TCTAAAAGCATCCACTACCAC-3′ and F, 5′-TCAGACAGGCTCTCAACAATAC-3′/R, 5′-TTCTAAAAGCATCCACTACCAC-3′) (Jones et al. 2001). These assays identified an additional GVBaV-positive sample. All amplicons were sequenced, and BLAST analysis of the BRV sequences (GenBank accession nos. MK501976 to MK501978) and GVBaV (GenBank accession nos. MK519228 to MK519230) revealed 92 to 98% and 96 to 99% nucleotide identity to GenBank accessions AF321572 and JQ388488, respectively. The positive samples were further assessed for the presence of the viruses using northern-blot hybridization with a digoxigenin-labeled probe that targeted the nontranslated region of BRV RNA2 and conserved motifs in the ribonuclease H domain of GVBaV. The results were in line with HTS and PCR detection and with the symptoms expressed in the three symptomatic plants. In addition, the episomal form of GVBaV was confirmed by positive results in RT-PCR using DNase-treated total nucleic acids and rolling circle amplification. To our knowledge, this is the first time that BRV and GVBaV were detected in currants in BiH. Given the lack of a currant certification program in the country, this information will be used in the development of best management practices for control of the two viruses and their associated diseases in both field and nursery operations.

Shallow Groundwater Quality and Its Controlling Factors in the Su-Xi-Chang Region, Eastern China

Understanding factors influencing groundwater quality is critical to the development of best management practices at the large watershed scale. In this study, the shallow groundwater (10–20 m depth) in the Su-Xi-Chang region, eastern China, was investigated as part of a monitoring program from 2007 to 2008 to analyze the regional groundwater quality as well as the hydrogeochemical processes and their controlling factors. Conventional physicochemical water parameters (pH, turbidity, electrical conductivity, dissolved oxygen, total phosphorus), major cations (Na+, Ca2+, Mg2+ and NH4+) and anions (Cl−, NO3− and SO42−) were measured. Hydrochemical methods and multivariate statistical methods were applied to analyze the hydrogeochemical signatures, origins, the similarities among the variables and to identify the main pollution sources in the groundwater. The results showed that (1) the concentrations of TDS (224.89–1086.70 mg/L) and turbidity (0.1–18.60 NTU) were higher than the class II groundwater quality standards in China and the WHO drinking water standards, (2) there were extremely high concentrations of ammonia (0.01–32.90 mg/L), with a mean value of 0.72 mg/L and (3) the nitrate concentrations (average value of 22.07 mg/L) exceeded the class III groundwater quality standards. The study also provided evidence that weathering, dissolution of carbonate, halite and silicate and cation exchange were the possible primary hydrogeochemical control mechanisms in the groundwater. The sources of ammonia, total phosphorus, sulfates and nitrates included rock–water interactions and anthropogenic activities. The groundwater administration of pollution sinks and sources, long-term legal frameworks and economic incentives should be improved to optimize watershed scale management in the context of rapid development in China.

Erosion and Sediment Control Best Management Practices in Agricultural Farms for Effective Reservoir Sedimentation Management at Cameron Highlands

For many years, lands in Cameron Highland have been opened and leveled for agricultural farming and intensive crop production. Land-disturbing activities such as agricultural operations that are conducted on regions with steep slopes leads to a high potential of soil erosion, sedimentation and landslide occurrences. As a results, this phenomenon producing large amounts of sediment transported and deposited to the receiving waters or reservoirs. The development of best management practices (BMPs) for agricultural activities is an important step towards minimizing the amount of soil erosion and landslide incidents in Cameron Highlands. Therefore, this Erosion and Sediment Control Guideline for Agricultural Activities in Hilly Area aims to minimize erosion and sedimentation from the agricultural area in Cameron Highlands especially in the scope of reservoir sedimentation management. There numbers of steps taken in order to establish this guidelines. The first step is to define the scope with the purpose of the guideline and conduct a literature review. In order to assess the quality and feasibility of the study to formulate the frameworks, engagement with stakeholders was conducted. Lastly is to undergo review and update based on the recommendations by related stakeholders. Finally, before the establishment of guidelines, all recommendations by related stakeholders are take in account that consists of Best Management Practices components which will be applied in the agricultural area to mitigate issues and problems especially in erosion control and reservoir sedimentation management. The Erosion Control Measures are including agronomic measures, soil management, mechanical methods and Rainwater Harvesting Techniques. Subsequently, these measures are used to apply in open or sheltered farming to control the erosion and sedimentation issues based on the erosion risk level. As a conclusion, this guideline will be useful for the stakeholders especially to local community, dam owners and local authority to mitigate and solve the issues related to erosion and sedimentation in hilly agricultural area.

Assessment of bacterial pathogens on edible macroalgae in coastal waters

In the Northeast USA, the aquaculture of macroalgae is a rapidly growing industry. Within this region, there are no established regulations for farm siting or methods of pathogen detection on macroalgae cultivated or harvested for human consumption. Bacterial pathogens from natural and anthropogenic sources may persist in coastal waters and can potentially contaminate macroalgae. During the winter growing season, sugar kelp Saccharina latissima and adjacent water were sampled from three sites of kelp aquaculture located in adjacent bays of ME, USA. Membrane filtration onto selective media detected Escherichia coli, Vibrio parahaemolyticus, and Vibrio alginolyticus in kelp and water samples at all sites, however plate counts were very low. The foodborne pathogens Salmonella enterica ser. Typhimurium, V. parahaemolyticus, and enterohemorrhagic E. coli O157:H7 were detected on enriched kelp samples from 83%, 78%, and 56% of sampling events, respectively, using molecular methods. Even with low bacterial levels, this frequency of detection confirms the risk of foodborne pathogens present on kelp and recommends the development of best management practices to control microbial growth during kelp harvest and processing. Bacterial plate counts from kelp samples often varied from those of water, indicating the importance of sampling the kelp directly, and that the association between bacterial pathogens on kelp and in the surrounding water should be further investigated. This study provides the first food safety assessment of sea vegetables in this region with the goal of providing data to enable the expansion of its industry.