United States Department Of Agriculture-Agricultural Research Service Research Articles

Development of a real-time PCR assay for detection and differentiation of Mycoplasma ovipneumoniae and a novel respiratory-associated Mycoplasma species in domestic sheep and goats.

A novel respiratory-associated Mycoplasma species (M. sp. nov.) of unknown clinical significance was recently identified that causes false positive results with multiple published PCR methods reported to specifically detect Mycoplasma ovipneumonaie, a well-known respiratory pathogen in small ruminants. This necessitates our objective to develop a real-time PCR (qPCR) assay for improved specificity and sensitivity, and more rapid detection and differentiation of M. ovipneumoniae and the M. sp. nov. in domestic sheep (DS) and domestic goat (DG) samples, as compared to a conventional PCR and sequencing (cPCR-seq) assay. Primers and probes were designed based on available M. ovipneumoniae 16S rRNA gene sequences in the GenBank database, and partial 16S rRNA gene sequences provided by the United States Department of Agriculture, Agricultural Research Service (USDA-ARS) for M. ovipneumoniae and M. sp. nov. USDA-ARS provided DS (n=153) and DG (n=194) nasal swab nucleic acid that previously tested positive for either M. ovipneumoniae (n=117) or M. sp. nov. (n=138), or negative for both targets (n=92) by cPCR-seq. A host 18S rRNA gene was included as an internal control to monitor for the failure of nucleic acid extraction and possible PCR inhibition. For samples positive by cPCR-seq, qPCR agreement was 88.0% (103/117; κ=0.81) and 89.9% (124/138; κ=0.84) for M. ovipneumoniae and M. sp. nov., respectively; 12 of 255 (4.7%) cPCR-seq positive samples were qPCR positive for both targets. Of samples negative by cPCR for both mycoplasmas, qPCR detected M. ovipneumoniae and M. sp. nov. in 6.5% (6/92) and 4.3% (4/92), respectively. Samples with discordant results between the cPCR and sequencing assay and the new qPCR were analyzed by target sequencing; successfully sequenced samples had identity matches that confirmed the qPCR result. The increased target specificity of this qPCR is predicted to increase testing accuracy as compared to other published assays.

Improvement of the Water Erosion Prediction Project (WEPP) model for quantifying field scale subsurface drainage discharge

In the poorly drained regions of the world, subsurface drainage systems are required to remove excess water for crop growth. Plastic drains alter a field’s hydrology by lowering the water table, reducing surface ponding, and reducing surface runoff. One significant concern with the use of subsurface drainage systems is adverse environmental effects because of the modification of the soil water dynamics. Some effects include the reduction of ecological services since wetlands change to croplands, water quality concerns, particularly sediment, nitrogen, and phosphorus losses in agricultural subsurface discharge water, as well as changes in the volume and timing of off-site discharges. Hydrological simulation models predict surface and artificial subsurface flow at different scales. Often in these models, Hooghoudt-based expressions are adapted in their internal algorithms. In this study, the Water Erosion Prediction Project (WEPP) model, developed by the United States Department of Agriculture - Agricultural Research Service (USDA-ARS) for soil and water conservation planning activities, was tested and improved to simulate surface and subsurface discharges. The modified WEPP model was tested and validated on an extensive dataset collected at four experimental sites managed by USDA-ARS within the Lake Erie Watershed. Predicted drainage discharges show Nash-Sutcliffe Efficiency (NSE) values ranging from 0.50 to 0.70, and Percent Bias ranging from −30% to +15% at daily and monthly resolutions. Evidence suggests that the WEPP model can be used to produce reliable estimates of subsurface flow with minimum calibration. Future work includes the extension of the model for quantifying subsurface drainage under controlled water table and watershed-scale simulations.

The Genetic Diversity of Cranberry Crop Wild Relatives, Vaccinium macrocarpon Aiton and V. oxycoccos L., in the US, with Special Emphasis on National Forests.

Knowledge of the genetic diversity in populations of crop wild relatives (CWR) can inform effective strategies for their conservation and facilitate utilization to solve agricultural challenges. Two crop wild relatives of the cultivated cranberry are widely distributed in the US. We studied 21 populations of Vaccinium macrocarpon Aiton and 24 populations of Vaccinium oxycoccos L. across much of their native ranges in the US using 32 simple sequence repeat (SSR) markers. We observed high levels of heterozygosity for both species across populations with private alleles ranging from 0 to 26. For V. macrocarpon, we found a total of 613 alleles and high levels of heterozygosity (HO = 0.99, HT = 0.75). We also observed high numbers of alleles (881) and levels of heterozygosity (HO = 0.71, HT = 0.80) in V. oxycoccos (4x). Our genetic analyses confirmed the field identification of a native population of V. macrocarpon on the Okanogan-Wenatchee National Forest in the state of Washington, far outside the previously reported range for the species. Our results will help to inform efforts of the United States Department of Agriculture Agricultural Research Service (USDA-ARS) and the United States Forest Service (USFS) to conserve the most diverse and unique wild cranberry populations through ex situ preservation of germplasm and in situ conservation in designated sites on National Forests.

Genetic data inform Yosemite National Park's apple orchard management guidelines

Societal Impact StatementYosemite National Park, California, USA has hundreds of apple trees in orchards that were planted in the 1800s by local settlers. These orchards played a cultural role in the early history of the land that was to become a national park. Most of Yosemite’s orchards are well over one hundred years old and have reached the end of their lifespan. Genetic data has facilitated the assignment of cultivar names to historic apple trees within Yosemite and this information will be used to develop an Orchard Management Plan. Yosemite will use this Plan to balance orchard conservation with other necessities such as reducing human‐wildlife conflict from bears that enter developed areas to consume fruit from the trees.Summary Yosemite National Park, California, USA has hundreds of historic apple trees that were planted within orchards in the 1800s, prior to the establishment of the park. These apple trees have been a concern within Yosemite for decades because their fruit attracts bears and other wildlife into visitor recreation areas, causing undesirable wildlife–human interactions. Herein, 361 of Yosemite's apple trees were genotyped to determine cultivar identities. The cultivar names of 117 apple trees were identified by matching genotypic data with genetic data available for an apple cultivar reference dataset for the United States Department of Agriculture‐Agricultural Research Service (USDA‐ARS) National Plant Germplasm System as well as collections maintained by other sources. An additional 92 trees were determined to be likely cultivars because they matched genotypes in a reference set of trees whose identities are not known. A total of 152 trees had unique genotypes that did not match reference datasets. Cultivar information, made possible by having digital genetic information available, will allow for the preparation of a more comprehensive Orchard Management Plan. As such, park managers will be able use the Plan to more effectively make decisions about balancing orchard conservation with other park necessities, including eliminating the human–wildlife conflict that results from bears entering developed areas to feed on the fruit trees.

The Birth, Growth and Future of Systems Approach

The Beyond Compliance Global team held an interview by video link with Dr Eric Jang, United States Department of Agriculture, Agricultural Research Service (USDA/ARS), now retired. His lab was based in Hawaii, where he continues to reside. Eric was an early advocate and one of the originators of the concepts for Systems Approach.

Landsat Hourly Evapotranspiration Flux Assessment using Lysimeters for the Texas High Plains

Evapotranspiration (ET) is one of the biggest data gaps in water management due to limited ET measurements, and further, spatial variability in ET is difficult to capture. Satellite-based ET estimation has great potential for water resources planning as it allows estimation of agricultural water use at field, landscape, and watershed scales. However, uncertainties with satellite data derived ET are a major concern. This study evaluates hourly satellite-based ET from 2001–2010 for the growing season (May–October) under irrigated and dryland conditions for both tall and short crops. The evaluation was conducted using observed ET from four large weighing lysimeters at the United States Department of Agriculture Agricultural Research Service (USDA-ARS) Conservation and Production Research Laboratory in Bushland, Texas. Hourly ET from satellite data were derived using the Mapping Evapotranspiration at High Resolution with Internalized Calibration (METRIC) model. Performance statistics showed that satellite-based hourly estimates compared to lysimeter measurements provided good performance with an root-mean-square error(RMSE) of 0.14 mm, Nash–Sutcliffe efficiency (NSE) of 0.57, and R2 of 0.62 for ET for dryland crops, and RMSE of 0.16, NSE of 0.63, and R2 of 0.65 for irrigated crops. METRIC provided accurate hourly ET estimates that may be useful for irrigation scheduling and other water resources management purposes based on the hourly assessment.

Quantifying the impacts of the Conservation Effects Assessment Project watershed assessments: The first fifteen years

T he United States Department of Agriculture (USDA) spends about US$6 billion each year on agricultural conservation programs to help producers and landowners implement conservation practices (CPs) and systems on their land. In 2003, the USDA Natural Resources Conservation Service (NRCS) entered into partnership with USDA Agricultural Research Service (ARS), USDA National Institute of Food and Agriculture (NIFA), other federal agencies, and many external partners to create the Conservation Effects Assessment Project (CEAP). The goal of CEAP is to quantify the environmental effects of CPs and programs and develop the science base for managing the agricultural landscape for environmental quality (Mausbach and Dedrick 2004; Duriancik et al. 2008). Conservation effects are assessed at national, regional, and watershed scales on cropland, grazing lands, wetlands, and for wildlife. As part of these efforts, CEAP initiated the Watershed Assessment Studies (WAS) component …

Soil health: model programs in the USA

Population growth, increasing drought, and natural resources degradation are significant global issues. Fortunately, management practices to improve soil health can address many of these issues in ways that are both good for the farmer and the environment. In 2012, the United States Department of Agriculture (USDA) Natural Resources Conservation Service initiated its “Unlock the Secrets in the Soil” campaign to assist farmers and ranchers with adopting soil health systems. Other notable efforts at the federal level include research and education projects by USDA Agricultural Research Service, National Institute of Food and Agriculture, and Sustainable Agriculture Research and Education program. The importance of improving soil health is also recognized far beyond federal government programs. The Soil Health Institute, a nonprofit charity, was established to safeguard and enhance the vitality and productivity of soil through scientific research and adoption. Crop commodity organizations are promoting soil health, such as the Soil Health Partnership. The Nature Conservancy is helping companies and private landowners incorporate soil health into their sustainability efforts. Such efforts are supported by the Foundation for Food and Agriculture Research, as well as by some of the leading global food companies such as General Mills. These are just a few of the many efforts to improve soil health in the USA. The significance of the expanding global population, natural resource challenges, and responsibilities to current and future generations truly make enhancing soil health a global imperative.

Effect of Steeping Regime on Barley Malt Quality and Its Impacts on Breeding Program Selection

When making malt, the endosperm is hydrated during steeping to make stored starch available for extraction. Differences in steep regime impact malt quality. Differences in malt quality results between the United States Department of Agriculture-Agricultural Research Service (USDA-ARS) and Montana State University (MSU) malt quality laboratories are primarily due to differences in steep regime and are reported herein. Evidence suggests that differences in steep regime in this study were primarily due to length of water immersion versus air rests, rather than other differences (e.g., temperature of steep, sorting of seed, or length of germination). The difference in steep regime caused a difference in the level of endosperm modification. To confirm this finding, three different steep regimes on seven different lines were tested and it was found that the impact on quality varied depending on the trait and in some cases on the genotype. The steep regime was found to have affected both moisture uptake and quality of hydration. Finally, the implications of these findings on malt quality analysis and breeding for malt quality are discussed.

Development of Neutralizing Buffered Peptone Water for Salmonella Verification Testing in Commercial Poultry Processing Facilities

Contaminated poultry continues to be a major source of human foodborne illness, and an estimated 2 million cases of foodborne illnesses can be traced to poultry each year in the United States. When the United States Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) became aware of concerns that sanitizers used by commercial poultry processors might produce inaccurate results in Salmonella verification testing of commercially processed poultry, FSIS requested that the USDA Agricultural Research Service (ARS) conduct research on the effect of sanitizer carryover on the recovery of Salmonella from test samples. After it was determined that sanitizer carry-over into test samples could reduce recovery of Salmonella, a neutralizing Buffered Peptone Water (nBPW) was formulated. The nBPW is now used in Salmonella verification testing in commercial poultry processing facilities in the U.S. and has been shown to enhance recovery of Salmonella from whole broiler carcasses in verification testing.

Characterization of atypical Flavobacterium columnare and identification of a new genomovar.

Journal of Fish DiseasesVolume 41, Issue 7 p. 1159-1164 SHORT COMMUNICATION Characterization of atypical Flavobacterium columnare and identification of a new genomovar J C García, J C García Aquatic Animal Health Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Auburn, AL, USASearch for more papers by this authorB R LaFrentz, Corresponding Author B R LaFrentz benjamin.lafrentz@ars.usda.gov orcid.org/0000-0001-7358-5108 Aquatic Animal Health Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Auburn, AL, USA Correspondence Benjamin R. LaFrentz, USDA-ARS Aquatic Animal Health Research Unit, Auburn, AL, USA. Email: benjamin.lafrentz@ars.usda.govSearch for more papers by this authorG C Waldbieser, G C Waldbieser USDA-ARS, Warmwater Aquaculture Research Unit, Thad Cochran National Warmwater Aquaculture Center, Stoneville, MS, USASearch for more papers by this authorF S Wong, F S Wong MSD Animal Health, MSD Animal Health Innovation Pte Ltd, Singapore City, SingaporeSearch for more papers by this authorS F Chang, S F Chang MSD Animal Health, MSD Animal Health Innovation Pte Ltd, Singapore City, SingaporeSearch for more papers by this author J C García, J C García Aquatic Animal Health Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Auburn, AL, USASearch for more papers by this authorB R LaFrentz, Corresponding Author B R LaFrentz benjamin.lafrentz@ars.usda.gov orcid.org/0000-0001-7358-5108 Aquatic Animal Health Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Auburn, AL, USA Correspondence Benjamin R. LaFrentz, USDA-ARS Aquatic Animal Health Research Unit, Auburn, AL, USA. Email: benjamin.lafrentz@ars.usda.govSearch for more papers by this authorG C Waldbieser, G C Waldbieser USDA-ARS, Warmwater Aquaculture Research Unit, Thad Cochran National Warmwater Aquaculture Center, Stoneville, MS, USASearch for more papers by this authorF S Wong, F S Wong MSD Animal Health, MSD Animal Health Innovation Pte Ltd, Singapore City, SingaporeSearch for more papers by this authorS F Chang, S F Chang MSD Animal Health, MSD Animal Health Innovation Pte Ltd, Singapore City, SingaporeSearch for more papers by this author First published: 26 April 2018 https://doi.org/10.1111/jfd.12778Citations: 9Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume41, Issue7July 2018Pages 1159-1164 RelatedInformation

Calibration and Validation of CSM‐CROPGRO‐Cotton Model Using Lysimeter Data in the Texas High Plains

AbstractTexas High Plains (THP), one of the most important food and fiber producing regions in the Ogallala Aquifer Region, currently faces rapid decline of groundwater levels. Predicted climate extremes and high temporal variability in growing season precipitation may require growers to pump more groundwater from the Ogallala Aquifer to meet higher crop water demand. The Decision Support System for Agrotechnology Transfer (DSSAT) Cropping System Model (CSM) is a widely used crop simulation tool for evaluating impacts of different water and crop management practices, including irrigation on crop yield and water use efficiency. In this study, CROPGRO‐Cotton module of the DSSAT was calibrated and validated using 2000, 2001, 2002, and 2010 irrigated lysimeter field data managed by the USDA‐ARS (United States Department of Agriculture ‐ Agricultural Research Service) Conservation and Production Research Laboratory at Bushland, TX. The lysimeter field consisted of four equal plots designated as NE, SE, NW, and SW. Crop growth characteristics including leaf area index (LAI), above ground biomass (AGB), evapotranspiration (ET), soil moisture, and lint yield of 2000‐NE, 2000‐SE, and 2001‐NE, were used for calibration and 2002‐NE, 2010‐NE, and 2010‐SE were used for validation. The calibrated and validated model was used to simulate the long term (1924–2012) crop yield and seasonal crop ET. During the calibration process, some of the cultivar and ecotype parameters that influence LAI, AGB, and lint yield were adjusted for better statistical results. Measured and simulated LAI, AGB, ET, soil moisture, and lint yield showed good agreement during calibration and validation as indicated by performance statistics such as r2 from 0.70 to 0.82, and percent error (PE) = −0.85 to 17.3% for LAI; r2 = 0.89 to 0.95, and PE = −7.36 to −13.66% for AGB; and r2= 0.90 to 0.94, and PE = 3.20 to 3.44% for ET during calibration and validation, respectively. The model underestimated ET during peak vegetative growth and development stage except in some circumstances. The calibrated and validated model was able to simulate lint yield and seasonal ET during a long term (1924–2012) historic period for Bushland, TX, under irrigated conditions. The calibrated model could be used to schedule ET based irrigation management practices in the THP and to estimate future ET for other modeling experiments.

N Response of No-Till Dryland Winter Triticale Forage

ABSTRACTTriticale’s forage-yield response to fertilizer nitrogen (N) is impressive on soils testing low in available N. Our objectives were to (1) quantify the forage-yield response of dryland winter triticale to applied N and residual nitrate N and (2) fit the yield data to a regression equation based on both applied N and residual soil nitrates and use the fitted equation to calculate economic optimum N rates for this crop (EONR). Winter triticale was direct seeded no-till into wheat or millet stubble for four site years at the United States Department of Agriculture, Agricultural Research Service (USDA-ARS) Central Great Plains Research Station. In each experiment (1995, 2007, 2009 and 2010) just prior to planting, the soil was sampled for nitrate-N. Replicated field plots were top-dressed with 0, 22, 34, 67, 90, 101 or 135 kg of N fertilizer per ha as urea-N. Yield and total biomass N was then measured in each plot in late spring each year. A relative yield N response equation, fitted to all four years of data, was able to explain 93% of the variability in yield. That equation provided reasonable EONR estimates that matched 87% of the EONRs calculated for individual years.

A history of Wind Erosion Prediction Models in the United States Department of Agriculture: The Wind Erosion Prediction System (WEPS)

Development of the Wind Erosion Prediction System (WEPS) was officially inaugurated in 1985 by United States Department of Agriculture-Agricultural Research Service (USDA-ARS) scientists in response to customer requests, particularly those coming from the USDA Soil Conservation Service (SCS), for improved wind erosion prediction technology. WEPS was conceived to address deficiencies in the then-20-yearold, predominately empirical Wind Erosion Equation (WEQ) widely used by SCS, and it sparked an endeavor that relied on novel laboratory wind tunnel research as well as extensive field studies to adequately uncover the physical relationships between surface properties and their susceptibility to and influence on wind erosion. The result is that WEPS incorporates many process-based features and other capabilities not available in any other wind erosion simulation model today. The USDA Natural Resource Conservation Service (NRCS) has now implemented WEPS as a replacement for WEQ within their agency. However, the road to achieve that replacement required years of close interaction between ARS and NRCS. NRCS had to ensure they had suitable national-scale WEPS databases before implementation. User input simplifications were required as well as modifications to the reports. Run-time concerns also arose during the lengthy testing and evaluation process. Many of these were strictly nonwind erosion science issues that had to be addressed before NRCS could officially implement and begin using WEPS within their agency. The history of the development of WEPS, its unique features and its solutions to selected critical issues encountered by NRCS prior to implementation are presented and discussed. Published by Elsevier B.V.

Long-Distance Movement of Bactrocera dorsalis (Diptera: Tephritidae) in Puna, Hawaii: How far can they go?

The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is considered a major economic threat in many regions worldwide, including the island of Hawaii in the Hawaiian archipelago. The need to control large populations over large areas helped initiate the USDA-ARS (United States Department of Agriculture–Agricultural Research Service) area-wide program. There is some discussion concerning the feasibility of eradication of the oriental fruit fly in areas on the island of Hawaii. An important aspect of population suppression is concerned with the ability of a species to move long distances. Suppression of an area may be futile if source populations outside of that area are capable of moving into and re-establishing populations within the suppression area. While most movement studies focus on the short-distance dispersal of flies from a single release point, this study aimed to explore the longer tails of the dispersal distribution suspected for many tephritids. Four releases of double-marked, sterile, laboratory-reared oriental fruit flies were completed. The releases took place at four different distances from an experimental fruit fly suppression zone within the Puna District on the island of Hawaii. Flies captured in methyl eugenol traps and protein bait traps were collected and examined for the mark. Many flies were recovered at unprecedented long distances (between 2–11.39 km) from the release point. Studies of this nature are notoriously difficult, as replication is not feasible and countless variables complicate procedures. However, we feel extremely fortunate to have collected data confirming results that, to our knowledge, have not been previously observed. These long-distance recaptures aid in understanding the long tails of spatial distribution of fly movement that have been suspected of this species, and will benefit consideration of dimensions for buffer zones that would be needed for the establishment of infestation-free or low-prevalence zones.

Economic Implications for the Biological Control ofArundo donax: Rio Grande Basin

3 Abstract. Giant reed, Arundo donax L., is a large, bamboo-like plant native to the Mediterranean region. It has invaded several thousand hectares of the Rio Grande riparian habitat in Texas and Mexico. The United States Department of Agriculture- Agricultural Research Service (USDA-ARS) is investigating four herbivore insects as potential biological control agents for giant reed. One of the most important reasons for targeting this invasive weed is to reduce its impact on available water supplies, especially in the Rio Grande Basin. This study examined selected economic implications of this program for agricultural water users in the U.S. The research included (a) estimating the value of the water saved (to agricultural purposes) by reduction of giant reed, (b) benefit-cost analyses, (c) regional economic impact analyses, and (d) an estimate of the per-unit life-cycle cost of water saved during a 50-year planning horizon (2009 through 2058). Positive results related to the benefit-cost ratio, economic impact analyses, and competitive results for the per-unit life-cycle cost of saving water are associated with the biological control project for giant reed. The benefit-cost ratio, calculated with normalized prices, indicates $4.38 of benefits for every dollar of public investment. According to 2009 results for the economic impact analyses, economic output is $22,000, value-added is $11,000, and no employment is supported by the water savings from giant reed. Additionally, the per-unit cost of water saved is $44.08, a value comparable to other projects designed to increase water supply for the region. These results indicate this program will have positive net economic implications for the U.S. and the Lower Rio Grande Valley of Texas.

USDA-ARS Research on Practices Compatible with Organic Agriculture for Management of Plant-Parasitic Nematodes on Vegetable Crops

Abstract The market for organically grown fruits and vegetables has been increasing in recent years, and research is vital for obtaining optimal quality and yields in organic production systems. Scientists at the United States Department of Agriculture-Agricultural Research Service (USDA-ARS) are investigating methods for managing plant-parasitic nematodes on these crops, and studies that involve practices appropriate for organic vegetable production are reviewed in this paper. The projects summarized here focus primarily on suppression of root knot nematode species, including Meloidogyne arenaria (Neal) Chitwood, M. hapla Chitwood, M. incognita (Kofoid and White) Chitwood and M. javanica (Treub) Chitwood. Projects from Florida include investigations of plant growth-promoting rhizobacteria (PGPR) and chitin amendments for management of nematodes on pepper (Capsicum annuum L.), muskmelon (Cucumis melo L.), and tomato (Solanum lycopersicum L.). In South Carolina, research programs focus on the identificatio...

PLANT EXPLORATION FOR FRUIT GENETIC RESOURCES IN SAKHALIN TERRITORY

ISHS XXVII International Horticultural Congress - IHC2006: II International Symposium on Plant Genetic Resources of Horticultural Crops PLANT EXPLORATION FOR FRUIT GENETIC RESOURCES IN SAKHALIN TERRITORY

USDA-ARS STRAWBERRY ANTHRACNOSE RESISTANCE BREEDING PROGRAM

Following an epidemic of anthracnose crown rot caused by Colletotrichum fragariae, the United States Department of Agriculture, Agricultural Research Service (USDA-ARS) initiated a breeding program in 1976 to develop anthracnose-resistant strawberry cultivars adapted to the southeastern USA. A standardized anthracnose screening protocol was developed and used to evaluate over 160,000 progeny from 448 crosses. These crosses were made at the Fruit Laboratory, Beltsville, MD, and the resultant seedlings were screened for anthracnose resistance in the greenhouse at the Small Fruit Research Station, Poplarville, MS. Among the resistant seedlings field-tested in Mississippi, 1515 selections were made based on yield, fruit quality, plant habit, and resistance to leaf scorch, common leaf spot, powdery mildew, and two-spotted spider mites. Four anthracnose-resistant breeding lines and one cultivar have been released from this program, and 96 elite anthracnose-resistant selections are currently maintained. Anthracnose-resistant selections from the USDA-ARS breeding program have been used as parents in breeding programs worldwide. Research conducted at Poplarville while developing the anthracnose resistant lines has resulted in a broad range of accomplishments including the first report in the USA of the anthracnose fruit rot pathogen, C. acutatum, on strawberry. Differences in the cultural, morphological, and molecular characteristics, the infection processes, and the pathogenicity of the three causal Colletotrichum species have been documented. Studies of the effect of cultural practices on the severity and spread of anthracnose in the field demonstrated that strawberries grown in soils with high nitrogen levels are more susceptible than plants grown in soils with lower nitrogen levels or those amended with calcium nitrate. It was also determined that the use of overhead irrigation and plastic mulch in strawberry fields resulted in more severe anthracnose than when drip irrigation and straw mulch were used. Fungicide efficacy was determined by in vitro, greenhouse, and field studies, and pathogen resistance to some fungicides was detected.

Rapid PCR detection of enterohemorrhagic Escherichia coli (EHEC) in bovine food products and feces

Although Escherichia coli (E. coli) O157:H7 is a major cause of foodborne illness, other types of E. coli can also cause illness. E. coli that possess the eae gene for attachment and effacing have the potential to cause disease. Many real-time, molecular-based assays have been developed to detect Enterohemorrhagic E. coli (EHEC) including E. coli O157:H7. However, no assay currently exists to detect the eae gene present in E. coli O157:H7 and other EHEC strains with a confirmed positive or negative result in less than 12 h. Raw beef food products (raw ground beef and raw boneless beef) at 25 and 375 g samples and bovine fecal samples at 2 g were inoculated with 10(1), 10(3), 10(4), and 10(5) organisms of E. coli O157:H7 to test the sensitivity of this assay. Fourteen different foodborne bacteria (including E. coli O157:H7) and 19 various E. coli strains, obtained from the United States Department of Agriculture-Agricultural Research Service (USDA-ARS) were tested for specificity. E. coli O157:H7 was detected at the level of 10(1) organisms in both 25 and 375 g samples of raw ground and raw boneless beef products as well as 2 g samples of bovine feces after pre-enrichment and concentration. None of the 14 foodborne bacteria screened for cross-reactivity was detected. All USDA E. coli strains confirmed to contain the eae gene were detected.