Search

With global warming and alterations of climatic patterns, greater frequency and severity of extreme events are observed in different regions. Drought is one of the most challenging extreme events, one which can cause catastrophic and long-lasting impacts on water availability, environment, agriculture, economy, and societies. This study investigates the historic changes of drought conditions in Southern Alberta which is home to communities whose main economic activity is agriculture, or otherwise related to environmental variables, and has experienced severe droughts in the past. We employed SPI (standardized precipitation index) and SPEI (standardized precipitation-evapotranspiration index) as drought indicators at 1-, 3-, 6-, 9-, and 12-month(s) timescales, to explore significant changes during 1980–2018. The indices were computed using a Daymet-gridded dataset for the South Saskatchewan River Watershed (SSRW). Constructed drought occurrence maps revealed that, on average, in nearly half of the analysis period, the region experienced drought. Comparing four past decades showed that drought impacted a larger area in 2000–2010, and the percentage of the area impacted by severe or extreme droughts significantly increased in the last two decades, compared to 1980–2000. Results show decreasing trends of drought in some areas, mainly in the headwaters of Bow River in the Rocky Mountains, and increasing trends in larger areas, mostly found downstream. The result denotes expansion of the dry/wet conditions to larger areas at longer timescales. The extent of areas with a significant trend (increasing/decreasing) was greater with longer timescales of drought indices. Comparing the two drought indices suggests significant differences, and outperformance of SPEI in detecting dry conditions.

Human-induced climate change through the over liberation of greenhouse gases, resulting in devastating consequences to the environment, is a concern of considerable global significance which has fu...

Blueberry maggot (Rhagoletis mendax Curran (Diptera: Tephritidae)) is a pest of blueberries (Vaccinium Linnaeus (Ericaceae)). Tephritid flies, including Rhagoletis Loew species, are susceptible to entomopathogenic fungi, but mortality levels depend on life stage targeted. We tested Metarhizium anisopliae (Metschnikoff) (Clavicipitaceae) strain S54 by application to pupae in the laboratory and using soil drenches in the laboratory and field. We hypothesised that younger (pre-diapause) pupae would be more susceptible to infection than older (post-diapause) pupae. In the laboratory, R. mendax emergence was reduced from 80% in the control to 57–60% with M. anisopliae. Rhagoletis mendax longevity was reduced by two days for both application timings, and mycosed cadavers increased by 9% and 27% with applications to younger and older pupae, respectively, compared to controls. In the field, R. mendax emergence was reduced by 50% with application to younger pupae compared to controls and applications to older pupae. The surfactant Silwet L77 caused reduced R. mendax emergence when pupae were dipped in suspensions. Even though M. anisopliae S54 did not greatly reduce emergence or longevity, infection was successful and younger pupae may be more susceptible than older pupae. Research with other M. anisopliae isolates against multiple life stages should be conducted and effects of soil variables on pathogenicity determined.

Solar photovoltaic (PV) and wind turbine technologies play a significant role in the world energy future. However, lack of awareness of the potential and relative value of renewables is a significa...

This manuscript, Part II of a climate change impacts assessment series, describes changes in CO2, CH4, and N2O emissions and soil carbon storage on a theoretical farm in the Keremeos Creek ...

The current study is Part I of a two-part assessment of climate change impacts on hydrology and farm-level Greenhouse Gas (GHG) emissions. The effects of climate change on spring and summer...

Arrival and spread of nonnative plant species can lead to changes in structure and function of the native insect fauna that include shifts in host use by native insect herbivores. Well-documented examples showing that these host shifts also lead to range expansion of native herbivores are, however, surprisingly rare. Evidence for range expansion requires an understanding of the insect’s distribution preceding arrival of exotic species. These data often are lacking. The North American psyllid Bactericera maculipennis (Crawford) (Hemiptera: Triozidae), a specialist herbivore on plants in the Convolvulaceae, has been hypothesized to have expanded its geographic range after colonizing the exotic field bindweed (Convolvulus arvensis L.; Convolvulaceae). Efforts to test this idea run into the same retrospective problems typical of these analyses, in that the psyllid’s host plant and its geographic distribution preceding arrival of C. arvensis are uncertain. We used the psyllid’s current association with C. arvensis to help identify its natal (pre-bindweed) host, reasoning that a host shift by this specialist herbivore would be more likely if natal and exotic species are closely related. Phylogenetic analyses of plants, rearing trials, and field records led us to target species of Calystegia R. Brown (hedge and false bindweeds; Convolvulaceae) as natal hosts of B. maculipennis. The current presence of B. maculipennis in regions lacking Calystegia but where C. arvensis is common supported the hypothesis that arrival of the exotic weed C. arvensis has indeed led to range expansion by this host-specialized psyllid.

Solar energy deployment is gaining greater attention as a sustainable source of energy that could alleviate aspects of the current climate crisis. Knowledge of the characteristics and economics of the solar electricity sector is required to integrate it in the energy generation and utilization mix. Unlike energy generation from fossil fuels, renewable energy sources have relatively low geographic density and are spread unevenly over large areas. Therefore, especially in cities, where space has greater value and opportunity costs, finding suitable spaces for implementing solar systems are essential to promote the use of solar technologies. Using remote-sensing data, the intricate topography of cities can be modelled, and insolation incident at each location can be estimated. A multi-criteria approach based on geographic information systems (GIS) and light detection and ranging (LiDAR) is used in this research to estimate rooftop photovoltaic electricity potential of buildings in an urban environment, the city of Lethbridge. An economic assessment is conducted utilizing present market prices to determine economically attractive rooftop PV systems. The total rooftop photovoltaic (PV) electricity potential is evaluated and compared with the local electricity demand. Effective expansion of solar power systems in the city is achieved by determining the geographic distribution of the best locations for exploiting the systems. This study estimates that the rooftop PV electricity generation potential of the city of Lethbridge is approximately 301 ± 29 (SD) GWh annually (almost 38% of its annual electricity consumption in 2016), and about 96% of the recognized potential rooftop PV systems are economically feasible. The results can assist in making informed policy decisions about investment in deployment of renewable energy generation.

Accurate and precisess estimation of spatio-temporal variability of solar radiation is critical. Some commonly used models evaluate this variability using methods in which the data required for estimating atmospheric attenuation may not be easily accessible for some study areas. Here, a daily solar radiation estimation method which uses ambient air temperature, a Digital Elevation Model, time of year, and monthly radiation estimates from Solar Analyst model has been proposed. The objective was to use air temperature-based empirical models for atmospheric transmissivity and diffuse fractions to vary total monthly radiation estimation from Solar Analyst, and then calculate total daily radiation as a fraction of total monthly radiation by applying a daily transmissivity-based ratio, as air temperature data are readily available at most locations on the planet. Results revealed that daily solar radiation can be estimated very well, with Mean Absolute Bias Error of around 40–53 W m−2 or Mean Bias Error of ± 10%, under all sky conditions at seven sites in diverse climate regions, using significantly less input data. The presented method is an improvement over previously used methods with Mean Bias Error of under 10% but more input parameters. Furthermore, the hourly solar radiation values can be calculated using the presented method using the ratio between daily and hourly radiation, for example from literature values and estimated daily insolation. The result also showed that the method is more useful for those stations with substantially higher numbers of sunny days than cloudy or partly cloudy days because the uncertainty of the model decreased from cloudy to sunny sky conditions. The implemented Digital Elevation Models environment of this method makes it applicable in many studies that need spatial estimation of solar radiation, especially for solar energy generation projects.

Pectobacterium atrosepticum is a pectolytic enterobacterium that causes blackleg in plants. Bacteriophage Peat2 was isolated from P. atrosepticum infected potato tissue and its genome sequenced. Analysis of the 48,659 bp genome revealed that Peat2 resembles the Myoviridae family Klebsiella pneumoniae bacteriophage JD001 and includes a CRISPR Cas 4 RecB-like nuclease. A lytic bacteriophage, Peat2 details provide important information for application as a biocontrol agent of disease caused by phytopathogenic P. atrosepticum.

The Palearctic psyllid Heterotrioza chenopodii (Reuter) (Hemiptera: Psylloidea: Triozidae) belongs to a complex of psyllids having plants in the Amaranthaceae (including the former Chenopodiaceae) as hosts. Geographic records for this introduced species in North America date from 1988, and include a number of coastal regions in eastern Canada, the Northeastern U.S., inland Virginia, coastal British Columbia, California, and wetland habitats near Lincoln, Nebraska. We updated North American records for H. chenopodii to include inland Washington and Oregon, southwestern Idaho, northcentral California, western Colorado, and southern and central Alberta. Psyllids were collected from Atriplex micrantha (Amaranthaceae) and unidentified Atriplex species, and from yellow sticky cards that had been placed in potato fields to monitor arthropod pests of potatoes. Traits of the adult psyllid, fifth-instar nymph, and egg used in identifying specimens are summarized.We provide the first photographs of the egg, fifthinstar nymph, and terminalia of the adult male psyllid. Rearing trials showed that H. chenopodii developed on A. micrantha, A. hortensis, Chenopodium album, C. berlandieri, and garden beet, Beta vulgaris, but failed to develop on Amaranthus tricolor. Development was most rapid on the two Atriplex species. Heterotrioza chenopodii has been shown in Europe to exhibit photoperiod-controlled dimorphism in wing size, producing a long-winged form in spring and summer, and a short-winged form in autumn. We confirmed in rearing trials and by field collections that populations of H. chenopodii from central Washington State also exhibit this dimorphism. Short-winged forms began replacing long-winged forms in field populations between late August and early October.

BACKGROUND: The primary care workforce is under-prepared to care for the growing older adult population. Extension for Community Healthcare Outcomes (ECHO) is a continuing education intervention that connects subspecialists and community health care providers (HCPs) via videoconferencing technology for didactic and case discussion sessions. METHODS: We asked participants to complete 8 to 12 educational telementoring sessions. These sessions were conducted between February 2016 and October 2017. Pre/post surveys of self-efficacy and frequency of practice behaviors were collected from eligible participants. RESULTS: 121 HCPs from multiple sites participated. Of these, 89 (non-trainee status) were eligible to complete surveys. Sixty-two participants (69.7%) completed pre/post surveys. Participants were queried regarding 15 geriatrics competencies. Self-efficacy significantly increased across all competencies after series participation (p < 0.05). Frequency of 8 out of 11 queried geriatrics-centered practice behaviors also increased significantly (p < 0.05). DISCUSSION: ECHO-Chicago Geriatrics offers a novel strategy for improving community HCPs’ geriatrics self-efficacy and frequency of geriatrics-centered practice behaviors.

Sharp-tailed grouse (Tympanuchus phasianellus) are an important component of northern grassland food webs, a reliable indicator species, and considered to be valuable to the preservation of biodiversity. Ecological stressors imposed on this species include habitat alteration, fragmentation, encroachment from agricultural development, insecticides, and the effects of climate change on prairie landscapes, all of which have the potential to alter food availability and trophic dynamics. Insects and spiders are an important food source for many grassland birds. The ecological roles of many arthropod species as prey and as contributors of other important ecosystem services remain relatively unexplored. This study examined esophageal crop contents from 164 plains sharp-tailed grouse (T. phasianellus jamesi) that were collected in 2017 and 2018 from three sites in southern and central Alberta, Canada. The remains of grasshoppers (Orthoptera: Acrididae, 18 species) were detected in 80% of esophageal crops collected in September, and 31% in October. Of the grasshopper samples, 91% and 63% respectively, were a single species identified as Dawson's grasshopper (Melanoplus dawsoni). Juvenile grouse consumed more grasshoppers than adult grouse in all cases. Studies on other gallinaceous game birds have also identified frequent consumption of single arthropod species, likely due to the range, catchability, and abundance of these species at certain times of year. This non-pest grasshopper species appears to form a significant part of the food supply for sharp-tailed grouse in the fall. Species-level arthropod ecology can contribute to a better understanding of ecosystem stability, optimal land management practices, and previously unexplored food web connections.

Blossom blight of seed alfalfa (Medicago sativa L.), caused by the fungal pathogens Botrytis cinerea and Sclerotinia sclerotiorum, is a potentially devastating disease on the Canadian Prairies in moist growing seasons. Monitoring the airborne spore concentrations of these pathogens could facilitate disease forecasting in the region. Nineteen seed alfalfa fields in southern Alberta, Canada were assessed throughout the growing seasons of 2014 and 2015. Trace levels of blossom blight symptoms were found in both years; however, plated floret and pod samples indicated that, overall, B. cinerea increased over the growing season whereas S. sclerotiorum decreased. In both seasons, Burkard 7-day volumetric spore samplers collected daily aerosol samples, and weather stations recorded environmental variables in three fields. Conidia and ascospores collected were quantified each day with a real-time polymerase chain reaction assay. Spore quantification indicated that both B. cinerea and S. sclerotiorum numbers remained low in July and increased in August. Both species had multiple days with high spore discharge, with seasonal maxima of 21,137 conidia and 2,265 ascospores. Exploratory model development indicated that spore discharge of both fungi is associated with environmental stressors such as large changes in relative humidity or high temperatures on preceding days.

The fungal pathogen Botrytis cinerea Pers.: Fr. infects flowers of many plant species, including alfalfa (Medicago sativa L.). In southern Alberta, blossom blight, caused in part by B. cinerea, reduces yields of seed alfalfa in cool, wet growing seasons. Previous studies have suggested that B. cinerea uses pollen to begin infection, and that the fungal-infected pollen may be vectored by alfalfa leafcutter bees (Megachile rotundata Fab.). A longitudinal greenhouse study was performed to investigate the role of pollen in the infection process of alfalfa florets by B. cinerea. The effects of pollination (pollinated vs unpollinated) and inoculation method (dry vs aqueous suspension) on floret and pollen infection was tested. Florets were harvested at 0, 24, 48 and 94 h after inoculation. Pollinated florets that were dry inoculated had significantly greater levels of infection (84%) than similarly inoculated unpollinated florets (38%, P

To suppress the occurrence of phytoplankton blooms dominated by cyanobacteria, control measures were implemented during the bottleneck stages of algal succession, overwintering and pre-recruitment, using a combination of chemical and biological algicides. First, water and sediment samples were incubated in the laboratory to determine the threshold temperature for cyanobacteria recruitment. Second, the functional characteristics of candidate algicides were screened. Third, an in situ pilot experiment was conducted to test the feasibility of this method. Our results indicated that (1) the recruitment of cyanophytes was initiated at 15°C, (2) H2O2 and rice straw were the optimum algicides and their optimal concentrations were 10 mg/L and 1 g/L, respectively, and (3) following the combined application of H2O2 and rice straw during overwintering and pre-recruitment, the biomass of cyanobacteria decreased by 27.1% during recruitment and by 53.2% during the first algal bloom. These results suggested that the com...

Background. Many adolescents underutilize preventive services and are underimmunized. Methods. To promote medical homes and increase immunization rates, we conceptualized and implemented a 3-year, 8-school pilot school-located vaccination collaborative program. We sought community, parent, and school nurse input the year prior to implementation. We selected schools with predominantly Medicaid-enrolled or Medicaid-eligible students to receive Vaccines For Children stock vaccines. Nurses employed by a mass immunizer delivered these vaccines at participating schools 3 times a year. Results. Over 3 years, we delivered approximately 1800 vaccines at schools. School administrators, health centers, and neighboring private physicians generally welcomed the program. Parents did not express overt concerns about school-located vaccination. School nurses were not able to participate because of multiple school assignments. Obtaining parental consent via backpack mail was an inefficient process, and classroom incentives did not increase consent form return rate. The influenza vaccine had the most prolific uptake. The optimal time for administering vaccines was during regular school hours. Conclusions. Although school-located vaccination for adolescents is feasible, this is a paradigm shift for community members and thus accompanies challenges in implementation. High principal or school personnel turnover led to a consequent lack of institutional memory. It was difficult to communicate directly with parents. Because we were uncertain about the proportion of parents who received consent forms, we are exploring Internet-based and back-to-school registration options for making the consent form distribution and return process more rigorous. Securing an immunization champion at each school helped the immunization processes. Identifying a financially sustainable school-located vaccination model is critical for national expansion of school-located vaccination.

Vegetation biomass was estimated for ungrazed pastures in two grassland ecoregions of Alberta, Canada, using multispectral 20 m SPOT satellite imagery and vegetation indices (VIs) for multitemporal imagery acquired throughout the growing season with associated field validation data at four study areas. Eight VIs were tested as well as four different types of transformations (linear, log, exponential, power) to ascertain the best predictive model. The Renormalized Difference Vegetation Index and Transformed Vegetation Index provided the best overall prediction (r2 = 0.68) of the amount of above-ground green biomass production, but only marginally better than the Normalized Difference Vegetation Index, Modified Simple Ratio, and other indices tested. When assessed by subregion, the Foothills Fescue study areas had higher discrimination (r2 = 0.72) and from more VIs than for Dry Mixedgrass (r2 = 0.61). In almost all cases a power function best described the form of the relationship between biomass and imager...

Background: ECHO (Extension for Community Healthcare Outcomes) is a telehealth educational program that uses videoconference technology to train community-based primary care providers (PCP’s) on the management of complex, chronic diseases. The main components of ECHO are didactics, case presentations, and case-based learning. ECHO was developed using the key principles of Social Cognitive Theory, Situated Learning Theory, and Community of Practice Theory. Objectives: In a prior study, we implemented an ECHO curriculum to improve management of resistant hypertension. The goals of the current study were to determine the extent to which the learning theories served as the foundation of the ECHO curriculum and identify opportunities to more effectively incorporate key principles of these theories into the ECHO program. Methods: We conducted semi-structured interviews with the nine clinicians who participated in the pilot curriculum. A community-based PCP assisted with question development, analysis, and manuscript preparation. We analyzed the interview transcripts using Directed Content Analysis. Results: Transcript analysis supported the contention that ECHO is based upon Social Cognitive Theory, Situated Learning Theory, and Community of Practice Theory. Comments from study participants highlighted benefits of each theory’s principles. Conversely, they also suggested we could improve our implementation of ECHO by adhering more closely to specific learning theory strategies. Conclusions: Our results indicate that ECHO indeed reflects the key tenants of Social Cognitive Theory, Situated Learning Theory, and Community of Practice Theory. Several aspects of our ECHO curriculum can be improved by more complete application of these learning theories.

This study reports on implementation of the CommunityRx system, a population health innovation that promoted clinic-community linkages via: a youth workforce (MAPSCorps) that conducted an annual community resource census; Community Health Information Specialists (CHIS) who supported cross-sector resource navigation; and a health information technology (HIT) for prescribing community resources. Between 2012–14, MAPSCorps identified 19,589 public-serving places in the 106mi2 implementation region. CHIS used these data to generate an inventory of nearly 15,000 health-promoting resources. The HIT platform was integrated with 3 electronic health record (EHR) systems at 33 clinical sites to map 37 prevalent health and wellness conditions to community resources; 253,479 personalized HealtheRx “prescriptions” were generated for approximately 113,000 participants. Participants found the HealtheRx very useful (83%); 19% went to a place they learned about from the HealtheRx. This study demonstrates the feasibility of using HIT and workforce innovation to bridge the gap between clinical and other health-promoting sectors.

We reared Oriental Migratory Locusts, Locusta migratoria manilensis (Meyen) in the laboratory from 3rd instar until adult death, at five constant temperatures (18, 21, 24, 27 and 30°C), and recorded life history variables. Temperature strongly influenced growth, development and behaviors. Growth and development rates were both positive linear functions of temperature, with low thermal thresholds for nymphal growth ( 15°C) and development (13°C). There was no mating at 18°C and no oviposition at 21 °C and below. Rearing temperature did not significantly influence mass at adult molt, except for the 18°C-nymphs who molted to adults with significantly smaller mass. Females laid their first egg pod significantly later at 24°C than at 30°C. There were strong but nonsignificant trends for low-temperature females to die earlier and lay fewer and lighter egg pods; 24°C-females averaged less than half the dry lifetime egg mass as 30°C-females. Our results show that L. m. manilensis is a warm-climate specie...

Secondary data sources are widely used to measure the built asset environment, although their validity for this purpose is not well-established. Using community-engaged research methodology, this study conducted a census of public-facing, built assets via direct observation and then tested the performance of these data against widely used secondary datasets. After engaging community organizations, a community education campaign was implemented. Using web-enabled cell phones and a web-based application prepopulated with the secondary data, census workers verified, modified, and/or added assets using street-level observation, supplementing data with web searches and telephone calls. Data were uploaded to http://www.SouthSideHealth.org . Using direct observation as the criterion standard, the sensitivity of secondary datasets was calculated. Of 5,773 assets on the prepopulated list, direct observation of public-facing assets verified 1,612 as operating; another 653 operating assets were newly identified. Sensitivity of the commercial list for nonresidential, operating assets was 61 %. Using the asset census as the criterion standard, secondary datasets were incomplete and inaccurate. Comprehensive, accurate built asset data are needed to advance urban health research, inform policy, and improve individuals’ access to assets.

The rate of climatic change over western North America (WNA) is quantified for 485 climate stations for the period 1950–2005. Additionally, six stations with quality long-term records were selected and analysed for the period 1906–2005. The indicators used were developed by the World Meteorological Organization (WMO) and the World Climate Research Program's Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI). From the 27 core indices, 4 temperature-based and 4 precipitation-based indicators were selected for in-depth analysis. The 8 million km2 study area is comprised of the 22 contiguous US states and 4 Canadian provinces west of the Mississippi River and Great Lakes. The results were divided into six general regions for interpretation and presentation. GIS interpolation of station-specific statistical output was completed to further aid in the identification of spatially coherent trends across WNA. Mean slopes were calculated over the whole study area, and by region, for each index, and then tested to determine if they were significantly different from zero. Results of the study show statistically significant historical climate trends across the study area. As expected in a region as geographically diverse as WNA, results differed between, and within, regions. Overall, temperature-based indicators showed a general warming trend over the entire study area, with the greatest increases along the North American Cordillera. The trends in precipitation-based indicators were more varied. General trends indicate moderately increasing precipitation volume and intensity over much of WNA. The strongest precipitation trends were found in areas with climate largely controlled by air masses originating over the Gulf of Mexico. Copyright © 2011 Royal Meteorological Society

The objective of this study was to determine whether a videoconference-based telehealth network can increase hypertension management knowledge and self-assessed competency among primary care providers (PCPs) working in urban Federally Qualified Health Centers (FQHCs). We created a telehealth network among 6 urban FQHCs and our institution to support a 12-session educational program designed to teach state-of-the-art hypertension management. Each 1-hour session included a brief lecture by a university-based hypertension specialist, case presentations by PCPs, and interactive discussions among the specialist and PCPs. Twelve PCPs (9 intervention and 3 controls) were surveyed at baseline and immediately following the curriculum. The mean number of correct answers on the 26-item hypertension knowledge questionnaire increased in the intervention group (13.11 [standard deviation (SD)]=3.06) to 17.44 [SD=1.59], P

Water supply from mountain snowmelt is a key resource on the Great Plains. Hydrologists recognize that water yields could be significantly reduced in a warmer climate, with negative impacts upon regional water supplies. Weather data availability is usually sparse in alpine watersheds. Consequently, distributed alpine snow hydrology models are generally limited to small instrumented watersheds. Such models are unable to simulate the timing and magnitude of spring streamflow at a sufficient spatial scale for watershed management. In this study, the Simulated Grid microclimate model (SIMGRID) was refined and applied to the simulation of snow water equivalent (SWE) and spring streamflow volume in the headwaters of the St. Mary basin of northern Montana. Relationships between winter precipitation and elevation were derived from snow survey data. The SWE mass balance algorithm was enhanced to include the effect of rain-on-snow conditions, and to differentiate between snowmelt and rainfall runoff. Multiple regre...

In Part I of this two-part study, the Simulated Grid microclimate model (SIMGRID) was modified and the new version validated on the St. Mary River watershed in northern Montana, using historical data. In Part II, future climate change scenarios are used to estimate spring streamflow (Q S ) for the 1961-2099 period. Relative to the base period (1961-1990), the model indicates median year Q S decline of 3 - 8% by the 2020s, 8 - 17% by the 2050s, and 15 - 27% by the 2080s. Mean onset of the spring pulse is projected to occur in early March or late February for the 2080s, 36 to 50 days earlier than for the 1961-1990 reference period. Model results generally indicate increased precipitation, but spring runoff volumes will decrease substantially, because the higher rain:snow ratio and shorter accumulation period will decrease snowpack volume. Overall, the results of this study indicate that the increased winter temperature resulting from anthropogenically-induced climate change, will result in shorter winters, reduced snowpack volume, and earlier spring snowmelt and runoff onset, resulting in substantial reductions in spring discharge.

Effects of essential oils derived from garden thyme, Thymus vulgaris L., patchouli, Pogostemon cablin (Blanco) Benth., and lemon-scent gum, Corymbia citriodora (Hook.) K. D. Hill & L. A. S. Johnson, on mortality of eggs, first-instar nymphs, and pupae, and on adult oviposition, of Bemisia tabaci (Gennadius) biotype B were determined under laboratory conditions. Three concentrations of essential oils, 0.125%, 0.25% and 0.5% (v/v), were applied in contact toxicity experiments. In separate experiments, 0.5% essential oil treatment was tested for repellency. Greater mortality was observed with increasing dose of essential oils. No phytotoxicity was observed on plants treated with these essential oils. First-instar nymphs were more sensitive to essential oil treatments, compared with eggs and pupae. The greatest effect was found with essential oil extracted from T. vulgaris, which reduced the survival rate of B. tabaci by 73.4%, 79.0% and 58.2% after treatment of eggs, nymphs and pupae, respectively, as compared with controls. In no-choice tests, the cumulative survival rates of B. tabaci females treated with T. vulgaris, P. cablin and C. citriodora were 46.4%, 38.8% and 26.8% lower, respectively, as compared with controls. In choice tests, the mean numbers of eggs laid on P. cablin, T. vulgaris and C. citriodora oil-treated plants were 74.5%, 59.0% and 48.0% fewer, respectively, than on control plants. Based on this study, essential oil derived from T. vulgaris possessed the greatest contact toxicity, while P. cablin oil exerted the strongest repellency to B. tabaci. Hence, these two oils could be used as effective and environmentally sustainable bio-insecticides for the control of B. tabaci.

Worldwide biological-control research has shown that the fungal entomopathogen Metarhizium anisopliae (Metschnikoff) is an alternative to chemical insecticides for controlling grasshoppers and locusts. The pathogenicity of two recently discovered isolates of M. anisopliae var. anisopliae Driver and Milner from Canadian soil to the key grasshopper pest Melanoplus bivittatus (Say) and the yellow mealworm, Tenebrio molitor L., was determined by means of laboratory bioassays. Insects were fed a single dose of 105 conidia suspended in sunflower oil on food (a standard-size lettuce wafer). Subsequent feeding activity, movement, and mortality were assessed daily. The isolates were equally pathogenic, and similar in pathogenicity to the industry standard, Green Guard (M. anisopliae var. acridum Driver and Milner). Treatment with the three isolates resulted in 50% grasshopper mortality in 5–6 days and 90% mortality in 6–7 days.

Agricultural systems in Canada are extensive in area, but not monitored or managed intensively. We developed informatics methods to better anticipate the severity, timing and geography of emerging pest risks to crops. The target insects, grasshoppers (Orthoptera: Acrididae), present special challenges in North America, as well as in China, because they occur as a complex of many species, only some of which represent significant risk to crops. We developed a Geographic Information System of insect and weather data in support of environmentally sustainable control methods. GIS-based maps of the outputs of simple weather-driven models of insect stage were provided to growers through a website containing current conditions. We combined delivery of this information with on-line training and non-technical tools for insect identification and selection of management actions. Color images for over 60 grasshopper species that assist recognition of pest versus non-pest species were provided on-line, with additional details provided in printed booklets (3500 copies were distributed free of charge). We also developed an iPhone application that provides similar information and assistance in recognizing species. We invited growers to attend on-line webinars (75 attendees) and in-person workshops (413 participants) for instruction on using the photographs and identification tips. A post-workshop survey completed by all the attendees indicated that most of the attendees (91%) scout their fields to check for the presence of grasshoppers, and that a majority of the farmers (90%) monitor or check their fields themselves, indicating that individual access to information is a valuable feature. Only 18 of the farmers at the workshops indicated that they had previously used species identification to determine pest risk status.

Climate and litter quality are primary drivers of terrestrial decomposition and, based on evidence from multisite experiments at regional and global scales, are universally factored into global decomposition models. In contrast, soil animals are considered key regulators of decomposition at local scales but their role at larger scales is unresolved. Soil animals are consequently excluded from global models of organic mineralization processes. Incomplete assessment of the roles of soil animals stems from the difficulties of manipulating invertebrate animals experimentally across large geographic gradients. This is compounded by deficient or inconsistent taxonomy. We report a global decomposition experiment to assess the importance of soil animals in C mineralization, in which a common grass litter substrate was exposed to natural decomposition in either control or reduced animal treatments across 30 sites distributed from 43°S to 68°N on six continents. Animals in the mesofaunal size range were recovered from the litter by Tullgren extraction and identified to common specifications, mostly at the ordinal level. The design of the trials enabled faunal contribution to be evaluated against abiotic parameters between sites. Soil animals increase decomposition rates in temperate and wet tropical climates, but have neutral effects where temperature or moisture constrain biological activity. Our findings highlight that faunal influences on decomposition are dependent on prevailing climatic conditions. We conclude that (1) inclusion of soil animals will improve the predictive capabilities of region- or biome-scale decomposition models, (2) soil animal influences on decomposition are important at the regional scale when attempting to predict global change scenarios, and (3) the statistical relationship between decomposition rates and climate, at the global scale, is robust against changes in soil faunal abundance and diversity.

This study examines regional relationships between climate, soil moisture, and pest grasshopper populations in Alberta. The objectives of this study are two-fold: (a) to investigate soil moisture as a potential predictor of pest grasshopper populations; and (b) to determine whether or not relationships between pest grasshopper populations and weather and soil moisture exist at the regional scale. Simple correlations and a modified chi-squared procedure are employed to investigate these relationships. Fall and spring soil moisture conditions appear to have some predictive capacity, showing strong associations to grasshopper abundance. Furthermore, regional relationships between temperature and soil moisture and the pest grasshopper populations are also identified. These relationships appear far stronger relative to low grasshopper populations, suggesting that population declines are easier to predict than outbreaks. Cool, wet weather in the spring and warm, dry weather in the fall and early winter are strongly associated with low populations.

Summary Background Enterovirus D68 (EV-D68) has been infrequently reported historically, and is typically associated with isolated cases or small clusters of respiratory illness. Beginning in August, 2014, increases in severe respiratory illness associated with EV-D68 were reported across the USA. We aimed to describe the clinical, epidemiological, and laboratory features of this outbreak, and to better understand the role of EV-D68 in severe respiratory illness. Methods We collected regional syndromic surveillance data for epidemiological weeks 23 to 44, 2014, (June 1 to Nov 1, 2014) and hospital admissions data for epidemiological weeks 27 to 44, 2014, (June 29 to Nov 1, 2014) from three states: Missouri, Illinois and Colorado. Data were also collected for the same time period of 2013 and 2012. Respiratory specimens from severely ill patients nationwide, who were rhinovirus-positive or enterovirus-positive in hospital testing, were submitted between Aug 1, and Oct 31, 2014, and typed by molecular sequencing. We collected basic clinical and epidemiological characteristics of EV-D68 cases with a standard data collection form submitted with each specimen. We compared patients requiring intensive care with those who did not, and patients requiring ventilator support with those who did not. Mantel-Haenszel χ 2 tests were used to test for statistical significance. Findings Regional and hospital-level data from Missouri, Illinois, and Colorado showed increases in respiratory illness between August and September, 2014, compared with in 2013 and 2012. Nationwide, 699 (46%) of 1529 patients tested were confirmed as EV-D68. Among the 614 EV-D68-positive patients admitted to hospital, age ranged from 3 days to 92 years (median 5 years). Common symptoms included dyspnoea (n=513 [84%]), cough (n=500 [81%]), and wheezing (n=427 [70%]); 294 (48%) patients had fever. 338 [59%] of 574 were admitted to intensive care units, and 145 (28%) of 511 received ventilator support; 322 (52%) of 614 had a history of asthma or reactive airway disease; 200 (66%) of 304 patients with a history of asthma or reactive airway disease required intensive care compared with 138 (51%) of 270 with no history of asthma or reactive airway disease (p=0·0004). Similarly, 89 (32%) of 276 patients with a history of asthma or reactive airway disease required ventilator support compared with 56 (24%) of 235 patients with no history of asthma or reactive airway disease (p=0·039). Interpretation In 2014, EV-D68 caused widespread severe respiratory illness across the USA, disproportionately affecting those with asthma. This unexpected event underscores the need for robust surveillance of enterovirus types, enabling improved understanding of virus circulation and disease burden. Funding None.

A genetic variant of the entomopathogenic fungus Metarhiziumanisopliae var. anisopliae, isolated from a soil in Alberta, Canada, from a location with a history of severe grasshopper infestations, was evaluated for pathogenicity in bioassays of living grasshoppers. Mortality in treated individuals drawn from a laboratory colony was 99% (LT50 = 6.7 days, LT90 = 9.6 days) at 12 days post-inoculation compared to 100% (LT50 = 4.1 days, LT90 = 5.8 days) mortality at 8 days in insects exposed to a commercial isolate of M. anisopliae var. acridum (IMI 330189). Experimental infection of field-collected grasshoppers under laboratory conditions with the native isolate of M. anisopliae var. anisopliae resulted in 100% (LT50 = 4.4 days, LT90 = 5.4 days) mortality attained within 7 days compared to 100% (LT50 = 4.7 days, LT90 = 6.3 days) mortality in 9 days in insects treated with M. anisopliae var. acridum. Amplification of fungal genomic DNA from the indigenous isolate with primers for the specific detection of M. anisopliae var. anisopliae produced a product almost 300 bp larger than expected based on previously known isolates. This is the first demonstration of a highly virulent, indigenous non-chemical control agent of grasshoppers in North America.

Objective: Breast milk transmission continues to account for a large proportion of cases of mother-to-child transmission of HIV-1 worldwide. An effective HIV-1 vaccine coupled with either passive immunization or short-term antiretroviral prophylaxis represents a potential strategy to prevent breast milk transmission. This study evaluated the safety and immunogenicity of ALVAC HIV-1 vaccine with and without a subunit envelope boost in infants born to HIV-1-infected women. Design: Placebo-controlled, double-blinded study. Methods: Infants born to HIV-1-infected mothers in the US were immunized with a prime-boost regimen using a canarypox virus HIV-1 vaccine (vCP1452) and a recombinant glycoprotein subunit vaccine (rgp120). Infants (n = 30) were randomized to receive: vCP1452 alone, vCP1452 + rgp120, or corresponding placebos. Results: Local reactions were mild or moderate and no significant systemic toxicities occurred. Subjects receiving both vaccines had gp120-specific binding serum antibodies that were distinguishable from maternal antibody. Repeated gp160-specific lymphoproliferative responses were observed in 75%. Neutralizing activity to HIV-1 homologous to the vaccine strain was observed in 50% of the vCP1452 + rgp120 subjects who had lost maternal antibody by week 24. In some infants HIV-1-specific proliferative and antibody responses persisted until week 104. HIV-1 -specific cytotoxic T lymphocyte responses were detected in two subjects in each treatment group; the frequency of HIV-1 specific cytotoxic T lymphocyte responses did not differ between vaccine and placebo recipients. Conclusion: The demonstration of vaccine-induced immune responses in early infancy supports further study of HIV-1 vaccination as a strategy to reduce breast milk transmission.

A study carried out in the Oldman River watershed in southern Alberta, Canada, to delineate potential surface water pollution sources revealed that the use of conventional raster-based digital elevation models (DEMs) and flow-direction algorithms resulted in the delineation of incorrect watershed boundaries. The inaccuracies resulted from the resolution of the available DEM, which is too coarse to represent the presence of anthropogenically modified terrain features, such as roads, ditches and canals, which can significantly alter overland flow paths. This observation prompted the development of the computer model RIDEM (Rural Infrastructure Digital Elevation Model). By incorporating ancillary data to refine anthropogenically modified overland flow paths into the grid-based watershed delineation process, the scale of runoff flow paths created with RIDEM is reduced below the scale defined by the representation of terrain with the DEM. RIDEM also resolves the inability of grid-based flow-direction algorithms to account for the split-flow patterns that occur in irrigated landscapes. The model outputs include a corrected flow-direction matrix, gross watershed boundaries, and road-induced dead drainages. The watershed areas derived with RIDEM differed by up to 49% from watersheds derived using a conventional DEM with a 20 m grid cell size. However, results of watershed boundaries could not be verified, because highly accurate watershed boundaries do not exist for our study area. Copyright © 2005 John Wiley & Sons, Ltd.

The entomopathogenic fungus Metarhizium anisopliae var. acridum is registered as a mycopesticide for acridid control in Africa and Australia. Traditionally, identification of M. anisopliae var. acridum infection in grasshoppers and locusts has relied upon development of fungal growth in infected cadavers. Conventional methods of detection of this entomopathogen in the environment and non-target organisms have been based on culture and bioassay. A PCR-based method for the detection of M. anisopliae var. acridum was developed. Sequence data from the distinct ITS rDNA regions facilitated the design of PCR primers that were used in PCR-based diagnostic assays for the detection of fungal DNA. The amplified sequence was 420 bp in length and specific to M. anisopliae var. acridum. Isolates of M. anisopliae var. anisopliae and M. flavoviride produced no PCR product with these primers. Other fungal entomopathogens, plant pathogens, mycopathogens, and soil saprophytes were also not detected by the pathogen-specific primers. The assay was also effective for the detection of M. anisopliae var. acridum DNA in the presence of soil DNA extracts and in infected grasshoppers.

An investigation into bacterial water quality problems was conducted on an interconnected stream and irrigation system within the Oldman River Basin of southern Alberta, Canada. Levels of indicator bacteria, including fecal coliforms, generic Escherichia coli and fecal streptococci, were repeatedly measured in streams and irrigation return canals of this river basin during the summer of 2001. Bacterial-loading segments of the irrigation/stream system were identified through a comparison of indicator bacteria levels in pairs of upstream and downstream sites. Mann-Whitney U-tests indicated that reservoirs significantly reduced bacterial counts. A temporal comparison of E. coli counts and river discharges suggested that these indicator bacteria do not originate from within in-stream sediments. Site-specific as well as cumulative inputs from a variety of non-point sources are likely to be responsible for the high downstream levels of indicator bacteria in this water system. The use of management practices such as in-stream reservoirs may significantly reduce contamination, and increase the quality of limited rural water supplies to allow their reuse and safe discharge into downstream water sources. The identification of bacteria-loading river/canal segments could also be used to prioritize restoration projects.

Des bioessais en cages et des tests sur le terrain nous ont permis d'evaluer l'efficacite d'insecticides organophosphores, pyrethrinoides et neonicotinoides, ainsi que des insecticides d'origine biologique, pour la reduction des populations du charancon des siliques de colza, Ceutorhynchus obstrictus (Marsham), un nouveau ravageur du canola au Canada. Un traitement au disulfoton, a la deltamethrine, au carbofuran, a l'oxydemethon-methyle ou au chlorpyrifos entraine une mortalite totale des charancons en cages en 48 h. Dans des parcelles ou des bandes dans des champs commerciaux en conditions naturelles de 1998 a 2001, seules la deltamethrine et la cyalothrine-lambda (toutes deux des pyrethrinoides) reduisent les densites de charancons de facon soutenue, meme lorsque les populations sont abondantes. Certaines annees, le chlorpyrifos reduit aussi significativement les nombres de charancons et les dommages aux recoltes, mais ses effets sont variables et son efficacite trop faible pour le controle des charancons aux densites de niveau epidemique. D'autres insecticides, tels que le spinosad, procurent un niveau de controle moyen et peuvent avoir un role dans la lutte contre les charancons, tout dependant de leur impact sur les insectes benefiques par comparaison a celui d'autres insecticides plus efficaces. Les traitements des graines de canola a l'imidaclopride, au lindane ou a l'acetamipride ne reduisent pas les dommages causes par les charancons. Il faudra faire des recherches supplementaires pour etablir les seuils economiques de densite de C. obstrictus dans les cultures de canola, pour evaluer l'impact des insecticides sur les ennemis naturels non cibles des insectes ravageurs du canola et determiner la possibilite d'integrer les agents chimiques a des strategies impliquant un controle biologique et des methodes particulieres de culture.

Blaesoxipha atlanis (Aldrich) is a common parasite of Melanoplus sanguinipes (Fabr.) in western Canada. We tested the hypothesis that parasitism by B. atlanis reduces food consumption by adult M. sanguinipes. Unparasitized grasshoppers serving as controls and grasshoppers infected with a single parasite larva were fed known quantities of freshly cut wheat (Triticum aestivum L. ‘Katepwa’) (Poaceae) leaves in the laboratory. The median development time in hosts of larvae of both male and female B. atlanis was 5.5 days. Two thirds of parasitized grasshoppers died within 9 days of infection, but all control insects survived. The dry mass of leaves consumed each day did not differ between parasitized insects that died and insects that survived parasitism; both groups fed less than unparasitized controls. The influence of parasitism on food consumption differed between host sexes, with feeding being depressed earlier and more severely in female than in male grasshoppers. The reduction in food consumption was most pronounced on day 6 after infection, when parasitized males and females consumed only 10% and 7%, respectively, of the food consumed by unparasitized controls. Parasite sex did not influence food consumption. Grasshoppers that survived parasitism by B. atlanis resumed feeding, consuming as much as unparasitized counterparts. Reduced food consumption limited the ability of grasshoppers to compensate for the nutritional demands of developing parasite larvae. As a consequence, parasitized grasshoppers lost body mass during the interaction. We propose that the temporary reduction in feeding by grasshoppers parasitized by B. atlanis that survive parasitism is not evidence of host regulation, but is consistent with a stress-induced alteration in host behaviour.

Background Abiotic and biotic stresses alter genome stability and physiology of plants. Under some stressful situations, a state of stress tolerance can be passed on to the offspring rendering them more suitable to stressful events than their parents. In plants, the exploration of transgenerational response has remained exclusive to model species, such as Arabidopsis thaliana. Here, we expand transgenerational research to include Brassica rapa, a close relative to economically important plant canola (Brassica napus), as it is exposed to the biotic stress of a double-stranded DNA virus Cauliflower mosaic virus (CaMV). Results Parent plants exposed to a low dose of 50 ng purified CaMV virions just prior to the bolting stage produced significantly larger seeds than mock inoculated and healthy treatments. The progeny from these large seeds displayed resistance to the pathogen stress applied in the parental generation. Differences in defense pathways involving fatty acids, and primary and secondary metabolites were detected by de novo transcriptome sequencing of CaMV challenged progeny exhibiting different levels of resistance. Conclusions Our study highlights biological and cellular processes that may be linked to the growth and yield of economically important B. rapa, in a transgenerational manner. Although much remains unknown as to the mechanisms behind transgenerational inheritance, our work shows a disease resistance response that persists for several weeks and is associated with an increase in seed size. Evidence suggests that a number of changes involved in the persistent stress adaption are reflected in the transcriptome. The results from this study demonstrate that treating B. rapa with dsDNA virus within a critical time frame and with a specified amount of infectious pathogen produces economically important agricultural plants with superior coping strategies for growing in unfavorable conditions.

Two species of grasshoppers (Melanoplus bivittatus and M. sanguinipes) tolerated high levels of miserotoxin (3-nitro-1-propyl-beta-D-glucopyranoside) in their diet. Miserotoxin is a causative agent in cattle poisoning when timber milkvetch (Astragalus miser) is consumed. Toxic effects were averted by grasshoppers in part by excretion of the intact glycoside. When the aglycone was administered, detoxification was achieved by two routes: by oxidation of the aglycone to 3-nitropropionic acid which was then conjugated with glycine, and by glucosylation of the aglycone to miserotoxin, in each case followed by excretion.

We conducted a field experiment to determine the direct and indirect effects of spraying two broad-spectrum insecticides with widely differing avian toxicities in grassland habitat on the survival and reproductive success of nesting songbirds. Three 56- ha plots were sprayed with Decis 5Fy, three plots were sprayed with Furadan 480Fy, and three plots were left unsprayed. Insecticides were applied at rates recommended for grasshopper control. Grasshopper (Orthoptera: Acrididae) density was measured throughout the spring and summer. Nests of chestnut-collared longspurs (Calcarius ornatus) were monitored to determine survival rates and nestling growth. Food habits of nestlings and parental foraging parameters were measured using esophageal ligatures and observations of parental foraging flights. Applications of both insecticides decreased grasshopper populations by more than 90%. Nevertheless, the number of grasshoppers in nestling diets was significantly decreased only in nests in Decis-sprayed plots. Total arthropod biomass delivered to the nestlings did not decrease in plots sprayed with either insecticide. Nestling weight and size were unaffected by insecticide spraying. Rate of prey delivery also did not change; however, by two weeks after spraying with Decis, parent longspurs were foraging almost twice as far from their nests as were birds in control plots ( p , 0.05) to maintain prey delivery rates. Clutch size and egg and nestling success were similar among treated and control plots within specific two-week periods during the season. Age-corrected brain acetylcholinesterase activities of longspur nestlings in plots sprayed with Furadan were significantly depressed compared to controls; a single case of insecticide-induced mortality was detected in a nestling that was severely infested with blowfly larvae. Nevertheless, success of nests with Furadan-exposed nestlings ( n 5 20) was greater than that in control plots during the two-week period following spray (n 5 19, p 5 0.03). The Baird's sparrow ( Ammodramus bairdii), an uncommon prairie species of conservation concern, was monitored using an index of productivity. The number of 3.14-ha census circles having productive Baird's sparrow territories was significantly lower in Furadan-sprayed plots than in unsprayed and Decis-sprayed plots; a larger number of sparrow territories were abandoned in Furadan plots.

Blaesoxipha atlanis (Aldrich) (Diptera: Sarcophagidae) is a common parasitoid of the grasshopper Melanoplus sanguinipes (F.) (Orthoptera: Acrididae) in western Canada. We tested the hypothesis that B. atlanis can develop as either a solitary or a gregarious parasitoid, and assessed the influence of parasitism on the growth and survival of infected grasshoppers. Males and females of M. sanguinipes were parasitized manually with one, two, or three first-instar larvae of B. atlanis in the laboratory. Parasitism was more deleterious to males than females of M. sanguinipes; females are larger than males. Host survival and longevity declined with the number of larvae per host in a sex-specific manner. In females, 39%, 24%, and 8% of hosts containing, respectively, one, two, and three sarcophagid larvae survived parasitism. Although 41% of single-parasitized males survived, all males containing more than one larva died. Variations in host quality as measured by dry mass explained much of the response to parasitism in male, but not female, hosts. Parasitoid larvae, apparently, did not cause significant physical damage to host organs and tissues but instead functioned as a metabolic sink. The greater metabolic activity associated with egg production could account for the relatively higher tolerance to parasitism of female, as opposed to male, grasshoppers. Developmental time, adult size, and percentage survival of B. atlanis declined with the intensity of parasitism, especially in parasitoids developing in male hosts. Females developing gregariously contained fewer ovarioles at eclosion than counterparts developing as solitary larvae. The mean body size of fieldcollected B. atlanis did not differ from that of laboratory-reared parasitoids developing singly in a host. Gregarious development is an alternative strategy to solitary development that may enable B. atlanis to maintain population numbers during periods of grasshopper scarcity.

This study assessed the safety of inactivated Mycobacterium vaccae as a candidate vaccine to prevent disseminated mycobacterial disease in children with HIV infection. 35 children ages 1-8 with CD4 counts > or =300/mm3 in New Hampshire, Boston and Chicago were randomised in a 2:1 schedule to receive a 3-dose series of intradermal M. vaccae vaccine (MV) or hepatitis B vaccine (HBV) at 2-month intervals. Immunisation was safe and well tolerated; 2-day median vaccine site in duration was 5 mm in MV recipients and 0 mm in HBV recipients (p < 0.001). There were no significantly different changes in viral load or CD4 count between the two vaccine groups. No PPD skin test conversions occurred after immunisation. MV is safe and well tolerated and deserves further evaluation as a vaccine to prevent mycobacterial disease in HIV-infected children.

Two species of melanopline grasshoppers ( Melanoplus bivittatus and M. sanguinipes ) tolerated high levels of 3-nitropriopionic acid (NPA) in their diet (LD 30 = 3 μ g g −1 ). The NPA was absorbed, conjugated to glycine, l -serine or l -glutamate and excreted in the frass as amides. Karakin was also consumed without ill effects. Karakin, a glucose triester of NPA, was apparently hydrolyzed in vivo , and the NPA was conjugated to the same amino acids. The conjugates were identified by NMR and ORD spectroscopy.

An experiment was conducted to determine whether spraying with a broad-spectrum pyrethroid insecticide in grassland habitat for the control of grasshoppers could affect nesting songbirds through the removel of insect food resources. Three 81 ha plots were sprayed at the recommended rate of Decis 5F (6.25 g deltamethrin ha−1). Paired control plots remained unsprayed. The density of (Acrididae) grasshoppers was monitored throughout the spring and summer. The nests of chestnut-collared longspurs (Calcarius ornatus) were monitored to determine the nest and nestling survival rates, size at fledging and food habits. Attributes of parental foraging were quantified. Food selection by parents and consumption by nestlings were measured using oesophageal ligatures. Grasshoppers accounted for >85% of the biomass of the nestling diet to spraying and this proportion increased throughout the season in unsprayed plots. Applications of Decis 5F initially reduced the grasshopper density by 93%. After spraying, parent birds switched to other arthropod taxa less affected by insecticide application; the overall biomass fed to nestlings was not significantly reduced although the acridid proportion declined to

The effect of conidial concentration, soil texture, and soil sterilization on the efficacy of Beauveria bassiana against ovipositing grasshoppers (Melanoplus sanguinipes) was investigated in a controlled environment. In the first experiment, mortality of female grasshoppers ovipositing into a sterile loamy-sand soil containing conidia of B. bassiana was measured. The prevalence of mortality increased as the concentration of conidia in soil increased, and a median lethal concentration of 10(4) colony-forming units (CFU) per gram of soil (dry weight) was observed. Conidia (10(2.9) to 10(3) CFU per abdomen) were recovered from the abdomens of grasshoppers ovipositing into sand containing 10(5.5) and 10(6) conidia per gram. Similar numbers of eggs were laid among treatments during the first oviposition period (1 to 7 days), but an effect of conidial concentration on eggs laid was observed during the second oviposition period (8 to 14 days). This was attributed to reduction in female numbers and not to reduction in fecundity independent of mortality. In a second experiment, grasshoppers oviposited into soils of three different textures (loamy-sand, sandy-loam, or clay-loam) that were amended with 10(5) B. bassiana conidia per gram and possessed either a viable or heat-killed microflora. There was no effect of soil texture on mortality of ovipositing grasshoppers, on the number of eggs laid, on positioning of egg pods in the soil profile, or on numbers of B. bassiana CFU recovered from female abdomens. However, a higher prevalence of mortality was observed for females ovipositing into the sterilized than nonsterilized sandy-loam and clay-loam soils. Substantial populations of fungi and bacteria were recovered from nonsterilized soils. The predominant fungi isolated from these soils were members of the genera Chrysosporium, Fusarium, Gliocladium, Penicillium, Rhizopus, and Trichoderma, whereas Bacillus, Paenibacillus, and Pseudomonas species were the most commonly isolated bacteria. This study demonstrates that ovipositing grasshoppers are susceptible to relatively low densities of conidia in soils of varying textures, but the soil microflora may have an adverse affect on the efficacy of B. bassiana in field soils. Copyright 1998 Academic Press. Copyright 1998 Academic Press