470 research outputs found
Iowa\u27s Plans and Preparations for the Possible Arrival of Asian Soybean Rust in 2005
Asian soybean rust, caused by the fungus Phakopsora pachyrhizi, can seriously reduce soybean yields and/or significantly increase the cost of soybean production when the disease occurs with high incidence and severity Until most recently, the continental United States was the only major soybean-producing area of the world where the disease was not known to exist. But on November 10, 2004, all that changed. On that date, the United States Department of Agriculture (USDA) and subsequently the Iowa Department of Agriculture and Land Stewardship announced that Asian soybean rust had been confirmed near Baton Rouge, Louisiana. The fields where the rust infestations were found were bulk soybean fields located on research farms belonging to Louisiana State University. At the time of the discovery of these initial infestations, most of the commercial soybean fields in Louisiana had been harvested. X.B. Yang, Iowa State University plant pathologist, is one of the leading experts on Asian soybean rust in the world and was flown down to Louisiana as a member of the USDA soybean rust detection assessment team to evaluate the rust outbreak
Asian Soybean Rust in the U.S.: One Year and Counting
Asian soybean rust is caused by the fungus Phakopsora pachyrhizi. This disease can seriously reduce soybean yields and/or significantly increase the cost of soybean production when the disease occurs with high incidence and severity Asian soybean rust was first identified in japan in 1902. The pathogen moved throughout Asia, Australia, and Africa throughout the 1900s before it was discovered in South America in 2000.In November 2004, Asian soybean rust was first discovered in the U.S. in Louisiana. At the time of the initial discovery of this disease in the U.S., most of the commercial soybean fields in the country were harvested. Nonetheless, additional Asian soybean rust infections were discovered on soybean and kudzu, the primary weed host for this fungus, in seven additional U.S. states in 2004 (Figure 1)
Factors Affecting the Development and Severity of Gossās Bacterial Wilt and Leaf Blight of Corn, Caused by Clavibacter michiganensis subsp. nebraskensis
Gossās bacterial wilt and leaf blight, which is caused by Clavibacter michiganensis subsp. nebraskensis, is a disease of corn (Zea mays) that has been increasingly reported across the Midwest since its reemergence in western Nebraska, northeastern Colorado, and southeastern Wyoming during the 2006 growing season. The objective of this study was to identify environmental and agronomic factors contributing to the incidence of the disease across the Corn Belt through a multistate survey conducted during the 2011 growing season. Of the 2,400 surveys distributed throughout nine states, 486 were returned with corn leaf samples, of which 70% tested positive for C. michiganensis subsp. nebraskensisusing an enzyme-linked immunosorbent assay. The agronomic data associated with each field were analyzed using classification and regression tree and random forest analyses to identify the factors that contributed most to Gossās bacterial wilt and leaf blight development. A Ļ2 test of independence was also done to determine relationships between certain variables and disease incidence. The two best predictors of Gossās bacterial wilt and leaf blight were hybrid resistance to Gossās bacterial wilt and leaf blight, as indicated by the seed companiesā score and a planting population density \u3e67,500 plants haā1. Other important predictors included longitude, planting date, crop rotation, percent residue, yield history, tillage, and growth stage. Relationships between glyphosate applications, foliar fungicide applications, and corn rootworm beetle with samples testing positive for C. michiganensis subsp. nebraskensis were also detected. These data contribute to our understanding of factors that increase the risk of Gossās bacterial wilt and leaf blight, and should enable more effective management practices to be adopted or developed
Environmental drivers of Ross River virus in south-east Tasmania, Australia: Towards strengthening public health interventions
In Australia, Ross River virus (RRV) is predominantly identiļ¬ed and managed through passive health surveillance. Here, the proactive use of environmental datasets to improve community-scale public health interventions in southeastern Tasmania is explored. Known environmental drivers (temperature, rainfall, tide) of the RRV vector Aedes camptorhynchus are analysed against cumulative case records for ļ¬ve adjacent local government areas (LGAs) from 1993 to 2009. Allowing for a 0- to 3-month lag period, temperature was the most signiļ¬cant driver of RRV cases at 1-month lag, contributing to a 23. 2% increase in cases above the long-term case average. The potential for RRV to become an emerging public health issue in Tasmania due to projected climate changes is discussed. Moreover, practical outputs from this research are proposed including the development of an early warning system for local councils to implement preventative measures, such as public outreach and mosquito spray programmes
Tetraamine Me6TREN induced monomerization of alkali metal borohydrides and aluminohydrides
Monomeric 1:1 complexes of MEH4 (M, E = Li, B, 1; Na, B, 2; Li, Al, 3; Na, Al, 4) and the tripodal tetradentate ligand (Me2NCH2CH2)3N (Me6TREN) have been prepared in good yields by refluxing in THF and allowing the solutions to cool slowly. X-ray diffraction studies show that the BH4 group binds to either Li or Na via three hydride bridges while the AlH4 group connects to Li via a single hydride bridge. Surprisingly, Me6TRENĀ·LiAlH4 represents the first monomeric contacted ion pair LiAlH4 derivative to be structurally characterized. In every case the tetraamine coordinates via all four of its Lewis basic nitrogen atoms. A similar protocol using the alkyl-rich borohydride MBEt3H also gives monomeric species (M = Li, 5; Na, 6). All complexes have been characterized in solution by multinuclear (1H, 7Li, 11B, 13C and 27Al, where appropriate) NMR spectroscopy which reveals excellent textbook examples of 1J coupling between B/Al and H in the cases of complexes 1-4 and between B and C in the cases of complexes 5 and 6
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