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 Content Type "Article - Refereed"
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- Acid Adapted Vibrio parahaemolyticus and Vibrio vulnificus Enhance Survival in Acidic EnvironmentsKoo, J.; Jahncke, M. L. (2006)
- Antimicrobial Effect of Acidified Sodium Chlorite (ASC) on Whole CroakerLee, B. D.; Koo, J.; Jahncke, M. L.; Kim, D.; Chung, D. O.; Eun, J. B. (2008)
- Apple Pollen Tube Growth Rates Are Regulated by Parentage and EnvironmentDeLong, Candace N.; Yoder, Keith S.; Combs, Leon; Veilleux, Richard E.; Peck, Gregory M. (American Society For Horticultural Science, 2016)A greater understanding of apple (Malus domestica) pollen tube growth rates can improve crop load management in commercial orchards. Specifically, applications of caustic bloom-thinning chemicals need to occur when enough, but not too many, flowers have been fertilized to achieve crop load densities that balance yields with marketable fruit sizes. In this study, the pollen tube growth rates of five crabapple (Malus sp.) cultivars were measured in the styles of three maternal cultivars at 12, 18, 24, and 30 °C after 24 hours in a growth chamber. Pollen tube growth rates were greatest for ‘Selkirk’ and ‘Thunderchild’ at 12 °C, and greatest for ‘Indian Summer’, ‘Selkirk’, and ‘Thunderchild’ at 24 °C. Pollen tube growth increased with increasing temperatures until 24 °C. There were minimal pollen tube growth rate increases between 24 and 30 °C. Overall, ‘Snowdrift’ had the slowest pollen tube growth rate of the five evaluated crabapple genotypes. At 24 and 30 °C, ‘Indian Summer’ and ‘Thunderchild’ pollen tubes reached the base of the style most frequently, and ‘Snowdrift’ pollen tubes the least frequently. Pollen tube growth rate was also influenced by the maternal cultivar, with Golden Delicious having relatively faster pollen tube growth than Fuji at 24 and 30 °C. Interactions among paternal and maternal genotypes as well as temperature after pollination reveal complex biological and environmental relationships that can be used to develop more precise crop load management strategies for apple orchards.
- Brown Marmorated Stink Bug in the Mid-Atlantic States: Assessing Grower Perceptions, Economic Impact, and ProgressDellinger, Theresa A.; Day, Eric R.; Pfeiffer, Douglas G. (U.S. Cooperative Extension System, 2016-08)Attendees at mid-Atlantic grower meetings were surveyed in 2012 and 2014 regarding their knowledge of the invasive brown marmorated stink bug (BMSB) and its impact. Responses to individual questions were paired and analyzed for independence between survey years. Despite a large-scale effort by Extension to inform growers and others about BMSB, there remains a clear need for more training on the identification of BMSB nymphs. Respondents also want more information on effective chemical options, scouting methods for BMSB, and BMSB biology, and they prefer to receive this information from Cooperative Extension.
- Can flaxseed lower cholesterol levels?Ju, Young H. (Virginia Cooperative Extension, 2017-10-13)Provides information about flaxseed and how it might help with lowering cholesterol.
- Challenges in enriching milk fat with polyunsaturated fatty acidsLanier, Jennifer S.; Corl, Benjamin A. (Biomed Central, 2015-06-12)Milk fatty acid composition is determined by several factors including diet. The milk fatty acid profile of dairy cows is low in polyunsaturated fatty acids, especially those of the n-3 series. Efforts to change and influence fatty acid profile with longer chain polyunsaturated fatty acids have proven challenging. Several barriers prevent easy transfer of dietary polyunsaturated fatty acids to milk fat including rumen biohydrogenation and fatty acid esterification. The potential for cellular uptake and differences in fatty acid incorporation into milk fat might also have an effect, though this has received less research effort. Given physiological impediments to enriching milk fat with polyunsaturated fatty acids, manipulating the genome of the cow might provide a greater increase than diet alone, but this too may be challenged by the physiology of the cow.
- Coleoptera of poultry manure in caged-layer houses in North CarolinaPfeiffer, Douglas G. (1980)
- Cucumber pollen germination and tube elongation inhibited or reduced by pesticides and adjuvantsGentile, A. G.; Vaughan, A. W.; Pfeiffer, Douglas G. (1978)
- Cultivar, Planting Date, and Row Spacing Effects on Mungbean Seed CompositionBhardwaj, H. L.; Hamama, A. A. (Canadian Center Of Science And Education, 2016-09-15)
- Determination of quality attributes of blue crab (Callinectes sapidus) meat by electronic nose and Draeger-Tube analysisSarnoski, Paul J.; Jahncke, Michael L.; O'Keefe, Sean F.; Mallikarjunan, Parameswarakumar; Flick, George J. Jr. (Haworth Press, 2008-01-01)In this study, five groups of sequentially spoiled crabmeat were evaluated by a trained sensory panel, and these results were compared with the findings from a Cyranose 320 Electronic Nose and Draeger gas analyzer. Using the electronic nose with filtered compressed breathing air yielded the best results. Although this approach resulted in 100% separation of the known groups, only 30% of the coded unknown samples were correctly identified. All 5 groups of samples analyzed using Draeger-Tubes were found to be significantly different at α=0.05 using a Tukey-Kramer ANOVA statistical procedure. The coded unknown samples were correctly identified at a rate of 83%. The simplicity and precision of this latter procedure may present opportunities for use of Draeger-Tubes by crab processing industries and other food processing industries as an objective method for quality control.
- Disruption of olfactory communication in oriental fruit moth and lesser appleworm in a Virginia peach orchardPfeiffer, Douglas G.; Killian, J. C. (1988)
- Double Play: The Need for 4-H to Partner in Youth SportsMartin, Perry D.; Kaufman, Eric K. (Extension Journal, Inc., 2017-10-19)Fewer children in the United States are playing team-based sports, and the trend is making national headlines. While there is no complete agreement as to the predominant reason for this trend, it is clear that a national conversation on this problem has begun, and Cooperative Extension holds the potential for getting kids back in the game. At its core, this conversation is about the healthful development of our children and their advancement as contributors to society. Cooperative Extension has decades of experience creating a "playbook" for youth development, and it is time to put that playbook into action.
- Effect of tree fertilization on numbers and development of pear psylla (Homoptera: Psyllidae), and on fruit damagePfeiffer, Douglas G.; Burts, E. C. (1983)
- Effect of tree fertilization on protein and free amino acid content and feeding rate of pear psylla (Homoptera: Psyllidae)Pfeiffer, Douglas G.; Burts, E. C. (1984)
- Effects of field applications of paraquat on densities of Panonychus ulmi (Koch) and Neoseiulus fallacis (Garman)Pfeiffer, Douglas G. (1986)Neoseiulus fallacis (Garman) is the most important acarine predator of the European red mite, Panonychus ulmi (Koch), in sprayed apple orchards in the eastern United States [Poe, S. L., and W. R. Enns. 1969. Predaceous mites (Acarina: Phytoseiidae) associated with Missouri orchards. Trans. Missouri Acad. Sci. 3: 69-82; Berkett, L. P., and H. Y. Forsythe. 1980. Predaceous mites (Acari) associated with apple foliage in Maine. Can. Entomol. 112: 497-502]. Populations of this predator are often present only at very low densities in Virginia orchards, however. The herbicide paraquat has been shown to be toxic to N. fallacis using slide-dip bioassays [Rock, G. C., and D. R. Yeargan. 1973. Toxicity of apple orchard herbicides and growth-regulating chcmicnls to Neoseiulus fallacis and twospotted spider mite. J. Econ. Entomol. 66: 1342-1343; Hislop, R. G., and R. J. Prokopy. 1981 . Integrated management of phytophagous mites in Massachusetts (U.S.A.) apple orchards. 2. Influence of pesticides on the predator Amblyseius fallacis (Acarina: Phytoseiidae) under laboratory field conditions. Protect. Ecol. 3: 157-1721. Paraquat is commonly applied in Virginia apple orchards in early spring while N. fallacis is still in its overwintering site in the orchard ground cover. The purpose of this study was to determine if field applications of paraquat affect densities of P. ulmi and its predator, N. fallacis, in the tree canopy. Slide-dip bioassay data, while very useful for comparing toxicity from topical applications of pesticides, are highly artificial and do not reflect other factors in mortality (contact with dried residues, behavioral responses, habitat modification). Other methods should be employed to complement slide-dip data (Dennehey, T. J., J. Granett, and T. F. Leigh. 1983. Relevance of slide-dip and residual bioassay comparisons to detection of resistance in spider mites. J. Econ. Entomol. 76: 1225-1230).
- Effects of modified atmosphere packaging on toxin production by Clostridium botulinum in raw aquacultured summer flounder fillets (Paralichthys dentatus)Arritt, Fletcher M.; Eifert, Joseph D.; Jahncke, Michael L.; Pierson, Merle D.; Williams, Robert C. (Int Assoc Food Protection, 2007-05-01)Packaging fishery products under vacuum atmosphere packaging (VAC) and modified atmosphere packaging (MAP) conditions can significantly extend the shelf life of raw, refrigerated fish products. There is considerable commercial interest in marketing VAC and MAP refrigerated (never frozen) raw fish fillets. The objective of this study was to determine if Clostridium botulinum toxin development precedes microbiological spoilage in raw, refrigerated flounder fillets. Aquacultured flounder (Paralichthys dentatus) individual fish fillets either were packed with a film having an oxygen transmission rate (OTR) of 3,000 cm3 m-2 24 h-1 at 22.8°C or were vacuum packaged or packaged under 100% CO2 with a film having an OTR of 7.8 cm3 m-2 24 h-1 at 21.1°C and were stored at 4 and 10°C. Samples were analyzed by aerobic plate count (APC) for spoilage and qualitatively for botulinum toxin with a mouse bioassay. The results demonstrate that flounder fillets (4°C) packaged with a film having an OTR of 3,000 were microbiologically spoiled (APC, >107 CFU/g) on day 15, but there was no toxin formation, even after 35 days of storage. However, at 10°C, toxin production occurred (day 8), but it was after microbial spoilage and absolute sensory rejection (day 5). Vacuum-packaged fillets and 100% CO2 fillets (4°C) packaged with a film having an OTR of 7.8 were toxic on days 20 and 25, respectively, with microbial spoilage (APC, >107 CFU/g) not occurring during the tested storage period (i.e., >35 days). At 10°C, in vacuum-packaged flounder, toxin formation coincided with microbiological spoilage (days 8 to 9). In the 100% CO2-packaged fillets, toxin formation occurred on day 9, with microbial spoilage occurring on day 15. This study indicates that films with an OTR of 3,000 can be used for refrigerated fish fillets and still maintain the safety of the product.
- Evaluation of methods to protect poultry house insulation from infestations by lesser mealworm (Coleoptera: Tenebrionidae)Despins, Joseph L.; Turner, E. Craig Jr.; Pfeiffer, Douglas G. (1991)Insecticide sprays Bnd paint barriers Applied to the surface of extruded polystyrene, and different types of insulation, were evaluated for prevention of lesser melllwonn, Alphitobius diapcn"nlls (Panzer), infestations. In a lahoratOly study, tetrachlOlvinphos 50 ¥lP and pirimiphosmethyl 7E on extruded polystyrene produced> 90% mortality in larval and adult lesser mealwonn populations 71 wk after application. These insecticide spray treatments, however, were not effective under conditions found in the manure pit of a high rise cage layer house. Our field study showed that Styrofoam SS"" and Ethafoarn 220''', were resistant. to lesser mealwonn infestations. Super IQ'" paint., a latex paint impregnated with chlorpyrifos, was also effective in protecting extruded polystyrene from infestations under field conditions.
- An examination of the relationships between leadership development approaches, networking ability, and social capital outcomesKaufman, Eric K.; Burbaugh, Bradley J. (Association of Leadership Educators, 2017-10-01)Participants in leadership development programs take part in multiple developmental experiences that can influence the composition of their social network and enhance social capital. However, further investment in such practices may be limited because little is known about the relationship between leadership development approaches, networking ability, and social capital. This study explores how common developmental approaches may contribute to social capital, taking into consideration the role networking ability plays in this relationship. This descriptive, correlational study included a sample of graduates (N= 231) from 15 statewide agricultural-based leadership development programs. Our findings reveal that: 1) Networking is an antecedent to social capital, 2) skill building and personal growth approaches to leadership development are significant predictors of networking ability, and 3) networking ability is a significant predictor of social capital.
- Expansion of the range of Pierce’s disease in VirginiaWallingford, Anna K.; Tolin, Sue A.; Myers, Ashley L.; Wolf, Tony K.; Pfeiffer, Douglas G. (2007)Pierce’s disease (PD) is a vascular disease of grapes caused by the bacterium Xylella fastidiosa Wells et al. and vectored by xylem-feeding sharpshooters (1). Symptoms of PD occur when bacteria proliferate the xylem; both the bacteria (2) and host responses to infection (3) block the flow of xylem fluid to the shoots. Affected grapevines show interveinal chlorosis, marginal necrosis with marginal yellow or red line (Figs. 1 and 2), green islands on shoot bark after normal tissue turns brown, and leaf abscission from the distal end of petioles, leaving characteristic "matchstick petioles" with necrotic tips (Fig. 3). Infection leads to vine decline, yield loss, and, within two to three years, vine death. Although the northern distribution of X. fastidiosa [* see Erratum] extends at least into New Jersey, observations of PD have been limited to vineyards on the Delmarva Peninsula and extreme southeastern Virginia; interior Virginia was considered at low risk of PD because of its low winter temperatures (lethal to the bacteria), based on the results of past research that showed lower pathogen populations in plants grown at low temperatures in a growth chamber (4). Recent warm winters have, however, increased our concerns about vulnerability of other Virginia vineyards to PD. Our objective was to conduct a state-wide survey of Virginia’s vineyards for presence of X. fastidiosa.
- Genetic diversity of plum curculio, Conotrachelus nenuphar (Coleoptera: Curculionidae) among geographical populations in the eastern United StatesZhang, Xing; Tu, Zhijian Jake; Luckhart, Shirley; Pfeiffer, Douglas G. (2008)
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