Virginia Cooperative Extension (VCE)
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Virginia Cooperative Extension is an educational outreach program of Virginia's land-grant universities: Virginia Tech and Virginia State University, and a part of the National Institute for Food and Agriculture, an agency of the United States Department of Agriculture.
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Browsing Virginia Cooperative Extension (VCE) by Department "Virginia Agricultural Experiment Station"
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- Mixed Infection of Strawberry Mottle Virus and Strawberry Mild Yellow Edge Virus in the Southeastern United StatesSamtani, Jayesh B.; Johnson, Charles S.; Flanagan, Roy III; Starke, Keith; Poling, Barclay; Martin, Robert (Virginia Cooperative Extension, 2017-10-25)More than 30 viruses and phytoplasmas are known to affect the genus Fragaria. Multiple viruses infecting strawberries (Fragaria xananassa Duch.) can severely affect plant productivity and reduce fruit quality. Complexes of viruses or mixed virus infections in strawberries in an annual production system were not identified in the southeastern United States prior to fall 2012. Within four to six weeks of transplanting strawberries in the fall of 2012 for annual plasticulture production, many growers in Virginia noticed some loss of crop stand and plants that exhibited yellowing along the leaf margins of several younger leaves (as seen in figs. 1 and 2). In some plants, these symptoms progressed to marginal necrosis.
- Oxygen stress reduces zoospore survival of Phytophthora species in a simulated aquatic systemKong, P.; Hong, C. (Biomed Central, 2014-05-13)Background The genus Phytophthora includes a group of agriculturally important pathogens and they are commonly regarded as water molds. They produce motile zoospores that can move via water currents and on their own locomotion in aquatic environments. However, zoosporic response to dissolved oxygen, an important water quality parameter, is not known. Like other water quality parameters, dissolved oxygen concentration in irrigation reservoirs fluctuates dramatically over time. The aim of this study was to determine whether and how zoospore survival may be affected by elevated and low concentrations of dissolved oxygen in water to better understand the aquatic biology of these pathogens in irrigation reservoirs. Results Zoospores of P. megasperma, P. nicotianae, P. pini and P. tropicalis were assessed for survival in 10% Hoagland’s solution at a range of dissolved concentrations from 0.9 to 20.1-mg-L-1 for up to seven exposure times from 0 to 72-h. Zoospore survival was measured by resultant colony counts per ml. Zoospores of these species survived the best in control Hoagland’s solution at dissolved oxygen concentrations of 5.3 to 5.6-mg-L-1. Zoospore survival rates decreased with increasing and decreasing concentration of dissolved oxygen, depending upon Phytophthora species and exposure time. Overall, P. megasperma and P. pini are less sensitive than P. nicotianae and P. tropicalis to hyperoxia and hypoxia conditions. Conclusion Zoospores in the control solution declined over time and this natural decline process was enhanced under hyperoxia and hypoxia conditions. These findings suggest that dramatic fluctuations of dissolved oxygen in irrigation reservoirs contribute to the population decline of Phytophthora species along the water path in the same reservoirs. These findings advanced our understanding of the aquatic ecology of these pathogens in irrigation reservoirs. They also provided a basis for pathogen risk mitigation by prolonging the turnover time of runoff water in recycling irrigation systems via better system designs.
- Phytophthora xstagnum nothosp nov., a New Hybrid from Irrigation Reservoirs at Ornamental Plant Nurseries in VirginiaYang, X.; Richardson, P. A.; Hong, C. (PLOS, 2014-07-29)
- Recycling Irrigation Reservoir Stratification and Implications for Crop Health and ProductionZhang, Haibo; Richardson, Patricia A.; Belayneh, Bruk E.; Ristvey, Andrew; Lea-Cox, John; Copes, Warren E.; Moorman, Gary W.; Hong, Chuanxue (2016)Recycling irrigation reservoirs (RIRs) are an emerging aquatic ecosystem and water resource of global significance. This study investigated the vertical distribution of water temperature, dissolved oxygen (DO), and pH in eight RIRs at two nurseries each in Virginia and Maryland from 2011 to 2014. Monomictic thermal stratification was observed from April to October in all RIRs, despite their shallow depths (0.75-3.89 m). The strongest stratification had a top-bottom temperature difference of 21.53°C. The top-bottom temperature difference was positively correlated with water column depth, air temperature, and daily light integral (p < 0.05). Wind speed did not impact the thermal stratification, likely due to their relatively small surface areas. Thermal stratification affected the vertical distribution of DO and pH. The top-bottom differences in DO and pH were greater during stratification periods than nonstratification periods. Water pH in all RIRs was higher at the top than at the bottom with the greatest difference of 4.16 units. Discovery and characterization of thermal stratification in RIRs helps understand water quality dynamics in this novel ecosystem and promote safe and productive water reuse for irrigation. Specifically, water withdrawal depths should be adjusted according to variations in temperature, DO, and pH during the stratification and nonstratification periods to mitigate pathogen risk and improve water treatment efficacy and crop production.
- Soil bacteria as sources of virulence signal providers promoting plant infection by Phytophthora pathogensKong, P.; Hong, C. (Nature Publishing Group, 2016-09-12)
- Soil inoculum production, survival, and infectivity of the boxwood blight pathogen, Calonectria pseudonaviculataDart, N. L.; Hong, C.; Craig, C. A.; Fry, J. T.; Hu, X. R. (2015)
- Supermarkets as Alternative Market Outlets for Virginia-Grown BerriesSamtani, Jayesh B.; Milteer, Gail M. (Virginia Cooperative Extension, 2019-02-28)Assesses the potential demand for berry crops among supermarkets in Virginia. Also examines the requirements producers must adhere to in order to successfully sell to supermarkets.
- Virginia Tech Shenandoah Valley Agricultural Research and Extension Center - 2003 Field Day Proceedings(Virginia Tech, 2003-07-23)The Shenandoah Valley AREC holds biennial field days to allow agricultural producers the opportunity to learn more about the research being conducted at the center and interact with those conducting the research.
- Virginia Tech Shenandoah Valley Agricultural Research and Extension Center McCormick Farm 2017 Field Day Proceedings(Virginia Tech, 2017)The Shenandoah Valley AREC holds biennial field days to allow agricultural producers the opportunity to learn more about the research being conducted at the Center and interact with those conducting the research.
- Virginia Tech Shenandoah Valley Agricultural Research and Extension Center McCormick Farm 2020 Field Day ProceedingsPent, Gabriel J. (Virginia Cooperative Extension, 2020-08-05)The Shenandoah Valley AREC holds biennial field days to allow agricultural producers the opportunity to learn more about the research being conducted at the Center and interact with those conducting the research.
- Virginia Tech Shenandoah Valley Agricultural Research and Extension Center – 2005 Field Day Proceedings(Virginia Tech, 2005-08-03)The Shenandoah Valley AREC holds biennial field days to allow agricultural producers the opportunity to learn more about the research being conducted at the center and interact with those conducting the research. The 2005 Field Day event commemorated 50 years of agricultural research.
- Virginia Tech Shenandoah Valley Agricultural Research and Extension Center – 2007 Field Day Proceedings(Virginia Tech, 2007-08-01)The Shenandoah Valley AREC holds biennial field days to allow agricultural producers the opportunity to learn more about the research being conducted at the center and interact with those conducting the research.
- Virginia Tech Shenandoah Valley Agricultural Research and Extension Center – 2009 Field Day Proceedings(Virginia Tech, 2009-08-05)The Shenandoah Valley AREC holds biennial field days to allow agricultural producers the opportunity to learn more about the research being conducted at the center and interact with those conducting the research.
- Virginia Tech Shenandoah Valley Agricultural Research and Extension Center – 2011 Field Day Proceedings(Virginia Tech, 2011-08-03)The Shenandoah Valley AREC holds biennial field days to allow agricultural producers the opportunity to learn more about the research being conducted at the center and interact with those conducting the research.
- Virginia Tech Shenandoah Valley Agricultural Research and Extension Center – 2013 Field Day Proceedings(Virginia Tech, 2013-08-07)The Shenandoah Valley AREC holds biennial field days to allow agricultural producers the opportunity to learn more about the research being conducted at the center and interact with those conducting the research.
- Virginia Tech Shenandoah Valley Agricultural Research and Extension Center – 2015 Field Day Proceedings(Virginia Tech, 2015-08-05)The Shenandoah Valley AREC holds biennial field days to allow agricultural producers the opportunity to learn more about the research being conducted at the center and interact with those conducting the research.