Manihot flabellifolia Pohl,wild source of resistance to the whitefly Aleurotrachelus socialis Bondar (Hemiptera: Aleyrodidae)

Aleurotrachelus socialis is one of the most important pests of cassava (Manihot esculenta Crantz) in the Neotropics. In Colombia, high whitefly populations can reduce crop yields by 79%; and although the farmers intensify the use of insecticides, this practice is highly contaminating, costly and leads to the development of resistance in the insect. An alternative for managing whitefly populations is to develop genetically resistant varieties. Wild parents of Manihot are a useful source of genes against pests for the cultivated species of cassava. Based on prior research that showed the existence of moderate-to-high levels of resistance to A. socialis in Manihot flabellifolia, a wild species of cassava, this study was proposed to characterize this new source of resistance, evaluating the biology and demographics of A. socialis on eight accessions of M. flabellifolia, a susceptible check (CMC-40) and a resistant (MEcu72) check. The averages of A. socialis longevity and fecundity on the accessions were not significantly different to MEcu72, but different from CMC-40 (P < 0.05). Development time was not significantly different, ranging from 35–40 days on accessions and MEcu72 and 33.5 days on CMC-40 (P < 0.05). In contrast, the population growth rate (r_m) was significantly lower on the M. flabellifolia accessions, with Fla 61 standing out with a growth rate 98 and 99% less than that obtained on MEcu72 and CMC-40, respectively. Once the resistant levels have been identified to A. socialis on the M. flabellifolia accessions, interspecific crosses of M. esculenta subsp. M. flabellifolia and backcross programs could be developed to incorporate the desirable characteristics from the wild relatives into elite progenitors of M. esculenta.     

Chronic mesenteric volvulus in a dog

A chronic, partial mesenteric volvulus was found on laparotomy of an adult Bernese mountain dog with a 4-month history of intermittent vomiting, diarrhea, and weight loss. The dog had elevated cholestatic and hepatocellular leakage enzymes, increased bile acids, azotemia, isosthenuria, and a hypokalemic, hypochloremic, metabolic alkalosis. The dog recovered fully following reduction of the volvulus.     

Detection of water in the LCROSS ejecta plume

Several remote observations have indicated that water ice may be presented in permanently shadowed craters of the Moon. The Lunar Crater Observation and Sensing Satellite (LCROSS) mission was designed to provide direct evidence. On 9 October 2009, a spent Centaur rocket struck the persistently shadowed region within the lunar south pole crater Cabeus, ejecting debris, dust, and vapor. This material was observed by a second "shepherding" spacecraft, which carried nine instruments, including cameras, spectrometers, and a radiometer. Near-infrared absorbance attributed to water vapor and ice and ultraviolet emissions attributable to hydroxyl radicals support the presence of water in the debris. The maximum total water vapor and water ice within the instrument field of view was 155 ± 12 kilograms. Given the estimated total excavated mass of regolith that reached sunlight, and hence was observable, the concentration of water ice in the regolith at the LCROSS impact site is estimated to be 5.6 ± 2.9% by mass. In addition to water, spectral bands of a number of other volatile compounds were observed, including light hydrocarbons, sulfur-bearing species, and carbon dioxide.     

Biodiversity is associated with indicators of soil ecosystem functions over a landscape gradient of agricultural intensification

Agricultural intensification has led to dramatic losses in biodiversity over the past several decades. Many studies have shown the effects of intensification on vegetation or soil communities at field or local scales. However, the functional significance of biodiversity may only appear at larger spatial and temporal scales, due to exchanges among local ecosystems throughout a landscape. To examine how patterns of biodiversity loss are reflected at larger spatial scales, plant and soil biodiversity and associated indicators of ecosystem functions were assessed in riparian areas over a 150 km² agricultural landscape in the Sacramento Valley of California. Publicly-available GIS data were first used to classify and select sites over the range of soils, topography and plant community types. Representative sites from the landscape were sampled for soil physiochemical properties, as well as microbial, nematode, and plant communities. Higher agricultural intensification, based on field and landscape indices, was negatively correlated with richness and diversity of plant and soil taxa, and was related to indicators of ecosystem functions, such as increased soil nitrate and phosphorus loading, decreased riparian health ratings, and lower soil carbon, soil microbial biomass and soil food web structure. Both field- and landscape-scale factors played important roles in the measured losses. The study area was composed of a wide array of soils, vegetation, and land management, indicating that the observed trends transcended site-specific conditions.