Untreated Fields Research Articles

The effect of Holistic Planned Grazing™ on African rangelands: a case study from Zimbabwe

Holistic Planned Grazing™ (HPG) is purported to have positive long-term effects on rangelands, enhancing ecosystem services. Given comparable environmental templates, but different management regimes, vegetation monitoring and landscape function analysis showed the Africa Center for Holistic Management (ACHM) at Dimbangombe had a significantly higher rangeland condition (composition, cover, standing crop and soil health) than adjacent Sizinda (SCR) and Monde (MCR) communal rangelands. Overall grazer density on ACHM is 42% higher than that of SCR (no data for MCR). Finer-scale satellite collar data for ACHM yielded a calculated stocking rate of 0,55 LSU ha-1 y-1 or 24 590 kg km-2, which constitutes high-density grazing. An energy flow estimate shows that the grazing resource would, on average, not be limiting for livestock on ACHM but limiting on SCR. HPG may include an element where kraals are inserted into degraded rangelands for a short period. Overall, ACHM shows stable perennial composition with smaller tufts significantly closer together. A similar result was visible in SCR where maize yields were visibly higher on kraaled areas than on adjacent untreated fields. HPG yields positive long-term effects on ecosystem services (soils and vegetation) and points to the HPG approach enhancing the sustainability of livestock and wildlife in this environment.

Impact of farm-made liquid organic nutrients jevamirtham and fish amino acid on growth and nutritional status in different season of Abelmoschus esculentus—a self-sustainable field trial

In organic agriculture, jeevamirtham (J) and fish amino acids (FAA) (Liquid organic nutrient bioformulations—LONBFs) were used to improve the plant growth and soil fertility. The effect of J and FAA in combination on the growth, nutritional status, and yield of plant has not been scientifically evaluated. In this study, liquid organic preparations of J and FAA were prepared and applied to okra plants individually and in combination (J + FAA). The experimental fields were designed as T1—untreated control field, T2—chemical fertilizer treated field, T3—jeevamirtham-treated field, T4—fish amino acid-treated field, and T5—mixture of jeevamirtham and fish amino acid-treated field. Microbial population and growth parameters were significantly increased in the T3, T4, and T5 fields. Higher chlorophyll, carbohydrate, and protein contents and more fruits were observed in plants from the T3, T4, and T5 fields than in plants from T2 and T1. The most favorable results were recorded in the J+FAA-treated field (T5). Results showed that LONBFs enhanced the beneficial microbial flora and fauna, higher yields, and nutritional products compared with chemical fertilizer and untreated fields. Hence, this eco-friendly LONBF could be added as an integral component to reduce the impact of chemical fertilizer in modern agriculture practice.

Thiamethoxam seed treatments reduce foliar predator and pollinator populations in sunflowers (Helianthus annuus), and extra-floral nectaries as a route of exposure for seed treatments to affect the predator, Coleomegilla maculata (Coleoptera: Coccinellidae)

Neonicotinoid seed-treatments are used frequently in sunflower production to prevent early-season herbivory, and have been implicated in declines in non-target species. Over three site-years, both insecticide treated (Cruiser®, rate: 0.25 mg a.i. (thiamethoxam)/seed) and untreated sunflower (Helianthus annuus [Family: Asteraceae]) fields were planted in Eastern and Central South Dakota. Foliar and subterranean predatory arthropod communities and pollinator populations were compared among the two treatments. A greenhouse study was performed to collect and quantify toxins in extra-floral nectar from treated and untreated sunflowers. A laboratory assay was performed to examine the effect of an artificial nectar diet laced with thiamethoxam or clothianidin on survival, fecundity and mobility of Coleomegilla maculata (De Geer [Coleoptera: Coccinellidae]). Seed-treated fields had significantly fewer above-ground natural enemies and pollinators than untreated fields, while subterranean predators were unaffected. Beetle flip-over times increased as concentration of thiamethoxam in diet increased, but clothianidin showed no effect. Neither toxin affected number of eggs oviposited by beetles, or size of developing oocytes. However, there was a negative correlation between increasing thiamethoxam concentration and number of developing eggs. Extra-floral nectar (EFN) collected from treated greenhouse-grown plants contained thiamethoxam (range: 1.23 ± 0.09 ppb to 4.83 ± 0.63 ppb), but no clothianidin. Toxin-laden EFN was identified as a potential route of exposure between beneficial arthropods and seed-applied neonicotinoids. Risks of neonicotinoid seed treatment use are discussed in the light of additional exposure pathways being confirmed.

Management Control Strategy of Devastated Tomato Borer, Tuta absoluta on Tomato Crop at El-Behira Governorate, Egypt.

Field experiments were conducted during two successive summer seasons, 2016 and 2017 to compare some methods of integrated pest management (IPM) program against T. absoluta with a control field (untreated field) from 3rd May to 3rd July at El- Berka village, Abu-Hommus district, El-Behira Governorate. Results showed that larval activity of T. absoluta during both two seasons, 2016 and 2017 was higher in control field (23.11±1.82 mean no. of larvae/leaf) than in IPM field program (2.71±0.40 mean no. of larvae/leaf). The numbers of male captures per trap per 3 days were increased during the experiment in an IPM field with overall mean no. of 201.29±4.81 males per trap per 3 days. However, the mean no. of male catches was 186.9±7.23 males/trap/3 days in control field with significant difference between them during two successive seasons. A thorough research program towards developing some sequence tactics in IPM program for T. absoluta including a foliar spray of Thiamethoxam 20%WG + Chlorantraniliprole 20%WG mixture, Flubendiamid 20%WG, Abamectin 8.4%SC, Spinetoram 12%SC and water mass trapping male moths using red plastic basin water trap (about 10 lure traps/ feddan) on tomato variety, K186. Such an approach would not only allow for reducing the pest, but also result in a better understanding management strategy of devastated tomato borer, T. absoluta in a given region.

Arthropod Abundance at Bustard Nesting Sites in the Saratov Trans-Volga Region

The results of study of the quantitative and qualitative composition of arthropod communities at potential nesting areas of great bustard (Otis tarda) in the Saratov Trans-Volga region are reported. Specific data collected at seven areas (two plowed fields, two fields of winter and spring wheat, two fallows of different ages, and virgin land) in 2012 are presented. Comparative analysis of some parameters of arthropod abundance and biomass on chemical-treated and untreated winter crop fields has been conducted. The results obtained have been compared to those of previous years. The current conditions for rearing of nestlings on natural fallow lands of different ages and on early-spring crop fields in the Saratov Trans-Volga region during the nesting period of O. tarda are favorable. The abundance and composition of arthropods in winter crop fields treated with a complex of chemicals do not meet the requirements for the rearing of O. tarda nestlings.

The effects of legume seeds on the lactation performance of dairy cows fed grass silage-based diets

The aim was to study if locally produced organic legume seeds as protein supplement could improve the performance of dairy cows. The experiment was a cyclic change over design were the control diet consisted of grass silage and barley (60:40) on a dry matter (DM) basis. Barley was replaced with rapeseed expeller (RSE), or isonitrogenous supplements of peas, untreated field beans (UFB), heat-treated FB (TFB) or a lower level of TFB (TFB-low) that provided the same dietary metabolizable protein concentrations as of UFB. None of the legume protein supplementations had effect on DM intake (DMI) neither on energy corrected milk yield compared to control. The RSE treatment increased milk (24.8 vs. 23.6 kg d-1) and protein yield (913 vs. 863 g d-1) compared to other protein supplements. Heat-treated FB had no effect on DMI, milk or protein yield compared to UFB. Only RSE resulted in improvements in dairy cows performance in relation to the control diet.

Effect of seedbed solarization on plant growth and yield of two rice varieties–BR11 and BRRI Dhan33

An experiment was carried out at RDRS Farm in Rangpur during the 2014 T. aman rice season to determine the impact of seedbed solarization on plant growth and yield of rice varieties, BR11 and BR33. Solarization was achieved by covering the seedbeds with transparent polythene sheet for four weeks prior to sowing. Seedlings of both varieties were raised on solarized and non-solarized seedbeds and later transplanted into the main field for comparison of growth and yield. Emergence, seedling height and weight, root length and weight were higher with seedlings raised on solarized seedbeds compared to seedlings from non-solarized seedbeds. Also root knot nematode galls decreased significantly on seedlings from solarized seedbeds compared to those from non-solarized seedbeds for both the varieties tested. The increase in height and weight of solarized seedlings enabled easy access for uprooting and transplanting seedlings in the main field within the recommended 20-25 days after sowing. When transplanted in untreated main fields, plants grown from the solarized seedlings of both the rice varieties had significantly less infestation of stem borer as compared to non-solarized plants. Grain yields obtained from solarized seedlings were 7% higher for BR11 and 9% higher for BR33 relative to normal seedlings.J. Bangladesh Agril. Univ. 15(1): 55-59, January 2017

Downy mildew resistance evaluation in 28 grapevine hybrids promising for breeding programs in Trentino region (Italy)

Downy mildew is a major grapevine disease caused by the biotrophic oomycete, Plasmopara viticola. Numerous disease resistance studies of diverse Vitis germplasm have been previously carried out to identify downy mildew resistance sources; however, ratings were mainly reported using leaf disc in vitro testing and foliage field assessment, or upon leaf and cluster field evaluations. In the current study, 28 grapevine hybrid cultivars were screened using leaf disc bioassay, for disease resistance characterization of both existing and wild-collected materials. 16 hybrids were identified as highly resistant or resistant, and will serve as relevant resistance donors in future pre-breeding and breeding programs. All grapevine hybrids were evaluated for foliar and cluster downy mildew resistance in an untreated field trial over three successive years. This study showed that the leaf disc bioassay provided some information on the resistance level of the genotypes under scrutiny, but it was a weak predictor of their resistance level under field conditions on leaves and even more on bunches. These findings are relevant to future applications in both traditional and marker-assisted breeding programs which promote sustainable viticulture.

Glyphosate, 1,1’- dimethyl-4,4’-bipyridinium dichloride and Atrazine induces changes in Soil organic carbon, bacterial and fungal communities in a tropical alfisol

The increasing use of agrochemicals for weed control has raised concerns about their ecotoxicological effects on soil micro-biota communities and soil functions which serve as indicators of soil quality. Thus, this study was conducted to evaluate the effects of continuous field applied herbicides glyphosate, paraquat, atrazine and their combined forms over a period of five years on soil organic carbon, bacterial and fungal population in Akure, Ondo State Nigeria. Soil samples from farmer’s field which have been exposed to continuous herbicide application were collected and analysed for physio-chemical properties, organic carbon, total bacterial and fungal population. Simultaneously, soil samples designated as control were collected from adjacent fields with no history of herbicide application and analysed. Results showed a significant (P=0.05) 86% and 128% increase in bacterial population from glyphosate and atrazine treated fields respectively and 42% decrease in paraquat and Glyphosate + paraquat fields when compared with the untreated field. A significant 35% decrease in fungal population was observed in fields applied with atrazine and a further 10% decrease in fungal populations in all herbicide treated fields irrespective of herbicide type and combinations when compared with the untreated field. These changes also correlates with the abundance of beneficial microbes such as Pseudomonas aeruginosa, Pseudomonas fluorescens, Proteus mirabilis, Aspergillus flavius with a probable influence on plant growth promotion and potentials for biodegradation of persistent herbicides. SOC, SOM and pH was significantly (P=0.05) increased in atrazine and atrazine + paraquat treated fields when compared with the untreated fields and other herbicide treatments.

Soil as a reservoir for road salt retention leading to its gradual release to groundwater

Road salt application elevates Na and Cl concentrations throughout the year in many surface water and groundwater systems. This study explores the role of soils in extending the lag time between road salt application and the delivery of Na and Cl to shallow groundwater in a temperate environment. Intact soil cores were collected near karst springs at both an urban and a rural site at distances of 1 m, 5 m, and 13 m from nearby roads that experience winter salting. Cores were manipulated in the lab to simulate various field conditions; treatments included irrigation with: 1) deionized (DI) water (DI group) as a control, 2) NaCl solution (salt group) to mimic prolonged exposure to road salt, or 3) NaCl followed by DI water (recovery group) to mimic winter road salting followed by dilute rainfall in spring. In the first NaCl irrigation of the salt and recovery groups, soils retained 62% of the applied Cl and 66% of the applied Na on average, which was largely stored in the porewater. Throughout the 5 week study, Ca, Mg, and K were elevated and the pH was depressed in leachate from salt group compared to DI group cores due to cation exchange. Likewise, cation exchange enhanced Na retention so that salt and recovery group cores retained half of the applied Na at the end of the experiment, compared to a quarter of the Cl. Na and Cl retention were greater for soils from the rural site, which is characterized by higher organic matter (OM) and sand content, faster infiltration, and lower bulk density than for the urban site, which has higher bulk density and more silt and clay. Furthermore, extractable Cl in untreated field soils was positively correlated with soil water content, OM, and sand content, suggesting that these properties may control retention. We assume Cl retention to be the result of porewater retention, microbial uptake, and chlorination of soil OM. After the addition of 2000 mg Cl to the salt group cores, non-conservative Cl behavior ceased because the retention capacity of the soils had been exhausted. Recovery rates during DI flushes of recovery group cores indicate that these soils slowly release Na and Cl for at least 2.5–5 months following salt application. This gradual release from soils helps to explain the year-round persistence of high salt concentrations in some surface waters and groundwaters.

Effects of heat treatment on protein feeds evaluated invitro by the method of estimating utilisable crude protein at the duodenum.

The effect of heat treatment on the protein value of field beans, lupins and peas was studied using an invitro method. Protein feeds were subjected to heat treatment for 30, 60 and 90min in forced air oven at 120, 140 and 160°C and in autoclave at 105, 120 and 135°C. The heat-treated protein feeds were incubated in buffered rumen fluid together with grass silage and barley in complete isonitrogenous diets. The gas production (GP) was recorded continuously, and ammonia-N (NH3 -N) concentrations were determined during the invitro incubation at 8, 24 and 48h and used to determine the utilisable crude protein (uCP) at the duodenum at 16h of incubation (uCP16 ). Heat treatments decreased the concentration of soluble crude protein and increased neutral detergent insoluble CP (NDICP) in all protein feeds compared to untreated. Inclusion of protein feeds to basal diet showed no increase in the uCP16 in untreated field bean diet and only a small numerical increase in the uCP16 concentrations from 160g/kg dry matter (DM) to 166 and 172g/kg DM in untreated lupine and pea diets, respectively, indicating high degradability of untreated feeds. Increasing the time and temperature of the heat treatment linearly increased the uCP16 concentrations in field bean and pea diets, but not in lupin diets. Autoclave treatment was more effective in decreasing uCP16 than oven treatment despite the lower temperatures used. However, the combination of highest temperatures and treatment time in autoclave increased acid detergent insoluble CP (ADICP) concentrations in protein feeds, indicating protein damage and decreased intestinal digestibility. Determining invitro uCP and ADICP shows to be a promising method for evaluating protein value in heat-treated animal feeds.

An energetics-based honeybee nectar-foraging model used to assess the potential for landscape-level pesticide exposure dilution.

Estimating the exposure of honeybees to pesticides on a landscape scale requires models of their spatial foraging behaviour. For this purpose, we developed a mechanistic, energetics-based model for a single day of nectar foraging in complex landscape mosaics. Net energetic efficiency determined resource patch choice. In one version of the model a single optimal patch was selected each hour. In another version, recruitment of foragers was simulated and several patches could be exploited simultaneously. Resource availability changed during the day due to depletion and/or intrinsic properties of the resource (anthesis). The model accounted for the impact of patch distance and size, resource depletion and replenishment, competition with other nectar foragers, and seasonal and diurnal patterns in availability of nectar-providing crops and wild flowers. From the model we derived simple rules for resource patch selection, e.g., for landscapes with mass-flowering crops only, net energetic efficiency would be proportional to the ratio of the energetic content of the nectar divided by distance to the hive. We also determined maximum distances at which resources like oilseed rape and clover were still energetically attractive. We used the model to assess the potential for pesticide exposure dilution in landscapes of different composition and complexity. Dilution means a lower concentration in nectar arriving at the hive compared to the concentration in nectar at a treated field and can result from foraging effort being diverted away from treated fields. Applying the model for all possible hive locations over a large area, distributions of dilution factors were obtained that were characterised by their 90-percentile value. For an area for which detailed spatial data on crops and off-field semi-natural habitats were available, we tested three landscape management scenarios that were expected to lead to exposure dilution: providing alternative resources than the target crop (oilseed rape) in the form of (i) other untreated crop fields, (ii) flower strips of different widths at field edges (off-crop in-field resources), and (iii) resources on off-field (semi-natural) habitats. For both model versions, significant dilution occurred only when alternative resource patches were equal or more attractive than oilseed rape, nearby and numerous and only in case of flower strips and off-field habitats. On an area-base, flower strips were more than one order of magnitude more effective than off-field habitats, the main reason being that flower strips had an optimal location. The two model versions differed in the predicted number of resource patches exploited over the day, but mainly in landscapes with numerous small resource patches. In landscapes consisting of few large resource patches (crop fields) both versions predicted the use of a small number of patches.

Insecticide resistance in cabbage aphidBrevicoryne brassicae

The lc50 values of imidacloprid 17.80% Sl, thiamethoxam 25% WG, acetamiprid 20% SP and dimethoate 30% EC were more in case of aphids collected from farmer's field (insecticide treated) than untreated field. The resistance factor (rF) of acetamiprid, imidacloprid, thiamethoxam and dimethoate was 85.06, 137.80, 13.50, and 44.17 folds, respectively.

Critical timings and methods of rodent pest management in groundnut (Arachis hypogaea L.) crop

The field efficacy of 2% zinc phosphide and 0.005% bromadiolone baits at two different crop stages for reducing rodent damage and yield loss in groundnut crop was evaluated. Trials were conducted at farmer's fields at villages Powat and Sehjomajra of district Ludhiana and village Kalsian of district Sangrur in Punjab (India). Reduction in rodent activity and damage was compared when given single treatment in the month of September at pod maturity stage (using either zinc phosphide or bromadiolone) and when given two treatments, first in the month of August (using zinc phosphide) at pod formation stage and second in the month of September (using bromadiolone). Results revealed significantly (P⩾0.05) higher reduction in rodent activity with two rodenticide treatments (79.98-92.18%) than single treatment (54.37-67.82%). The reduction in rodent damage compared to untreated reference fields was found to be 87-100% in fields given two treatments and 44.43-87.54% in fields given single treatment.

A comparative study of the extent of cerebral microvascular injury following whole-brain irradiation versus reduced-field irradiation in long-term survivors of intracranial germ cell tumors

Background and purposeRadiation-induced cerebral cavernous malformation reflects post-irradiation impairment of cerebral microcirculation. Our purpose was to determine effects of radiation field size and dose on the extent of developing cavernous malformations in long-term survivors of intracranial germ cell tumors (GCTs). MethodsThe study involved 34 patients with a history of intracranial GCTs treated with either whole-brain or reduced-field irradiation and undergoing magnetic resonance (MR) imaging with a mean follow-up of 18.5years. The number of cavernous malformations on T2*-weighted MR images between whole-brain and reduced-field irradiation groups as well as between high- (50.2Gy) and low-dose (24.4Gy) fields were compared. ResultsA total of 235 cavernous malformation lesions were observed in 32 of 34 patients (94.1%). The mean number of lesions was 2.3 times as high in the whole-brain group as in the reduced-field group (P=0.00296). The number of lesions in high-dose fields was significantly larger than in low-dose (P<0.000001) or untreated fields (P<0.001). ConclusionRadiation field size and dose were positively associated with the number of cavernous malformations developed. Cavernous malformations detected on MR imaging can be used as a surrogate marker for microvascular injury following intracranial irradiation in long-term cancer survivors.

Genetic Analysis of the Aspergillus flavus Vegetative Compatibility Group to Which a Biological Control Agent That Limits Aflatoxin Contamination in U.S. Crops Belongs.

Some filamentous fungi in Aspergillus section Flavi produce carcinogenic secondary compounds called aflatoxins. Aflatoxin contamination is routinely managed in commercial agriculture with strains of Aspergillus flavus that do not produce aflatoxins. These non-aflatoxin-producing strains competitively exclude aflatoxin producers and reshape fungal communities so that strains with the aflatoxin-producing phenotype are less frequent. This study evaluated the genetic variation within naturally occurring atoxigenic A. flavus strains from the endemic vegetative compatibility group (VCG) YV36. AF36 is a strain of VCG YV36 and was the first fungus used in agriculture for aflatoxin management. Genetic analyses based on mating-type loci, 21 microsatellite loci, and a single nucleotide polymorphism (SNP) in the aflC gene were applied to a set of 237 YV36 isolates collected from 1990 through 2005 from desert legumes and untreated fields and from fields previously treated with AF36 across the southern United States. One haplotype dominated across time and space. No recombination with strains belonging to VCGs other than YV36 was detected. All YV36 isolates carried the SNP in aflC that prevents aflatoxin biosynthesis and the mat1-2 idiomorph at the mating-type locus. These results suggest that VCG YV36 has a clonal population structure maintained across both time and space. These results demonstrate the genetic stability of atoxigenic strains belonging to a broadly distributed endemic VCG in both untreated populations and populations where the short-term frequency of VCG YV36 has increased due to applications of a strain used to competitively exclude aflatoxin producers. This work supports the hypothesis that strains of this VCG are not involved in routine genetic exchange with aflatoxin-producing strains.

Male mosquitoes as vehicles for insecticide.

BackgroundThe auto-dissemination approach has been shown effective at treating cryptic refugia that remain unaffected by existing mosquito control methods. This approach relies on adult mosquito behavior to spread larvicide to breeding sites at levels that are lethal to immature mosquitoes. Prior studies demonstrate that ‘dissemination stations,’ deployed in mosquito-infested areas, can contaminate adult mosquitoes, which subsequently deliver the larvicide to breeding sites. In some situations, however, preventative measures are needed, e.g., to mitigate seasonal population increases. Here we examine a novel approach that combines elements of autocidal and auto-dissemination strategies by releasing artificially reared, male mosquitoes that are contaminated with an insecticide.MethodologyLaboratory and field experiments examine for model-predicted impacts of pyriproxyfen (PPF) directly applied to adult male Aedes albopictus, including (1) the ability of PPF-treated males to cross-contaminate females and to (2) deliver PPF to breeding sites.Principal FindingsSimilar survivorship was observed in comparisons of PPF-treated and untreated males. Males contaminated both female adults and oviposition containers in field cage tests, at levels that eliminated immature survivorship. Field trials demonstrate an ability of PPF-treated males to transmit lethal doses to introduced oviposition containers, both in the presence and absence of indigenous females. A decline in the Ae. albopictus population was observed following the introduction of PPF-treated males, which was not observed in two untreated field sites.Conclusions/SignificanceThe results demonstrate that, in cage and open field trials, adult male Ae. albopictus can tolerate PPF and contaminate, either directly or indirectly, adult females and immature breeding sites. The results support additional development of the proposed approach, in which male mosquitoes act as vehicles for insecticide delivery, including exploration of the approach with additional medically important mosquito species. The novelty and importance of this approach is an ability to safely achieve auto-dissemination at levels of intensity that may not be possible with an auto-dissemination approach that is based on indigenous females. Specifically, artificially-reared males can be released and sustained at any density required, so that the potential for impact is limited only by the practical logistics of mosquito rearing and release, rather than natural population densities and the self-limiting impact of an intervention upon them.

Overwintering Refuge Sites forMegacopta cribraria(Hemiptera: Plataspidae)

Megacopta cribraria F. (Hemiptera: Plataspidae) was first reported in the United States near Atlanta, Georgia, in fall 2009 (Suiter et al. 2010, J. Integr. Pest Manag. 1: 1–4) and has since spread throughout the southeastern United States (http:// www.kudzubug.org/distribution_map.cfm). In Asia and the United States, it is commonly associated with its preferred host plant, kudzu, Pueraria montana Lour (Merr.) var. lobata (Willd.) (Fabales: Fabaceae) (Medal et al. 2013, Fla. Entomol. 96: 631–633). Nonetheless, M. cribraria has emerged as a significant pest of soybean, Glycine max (L.) Merrill and may damage a few other legumes in the United States (Eger et al. 2010, Insecta Mundi 0121: 1–11; Hu and Carroll 2012, htpp://agfax.com/2012/05/18/Alabama-soybean-kudzubugs-making-their-move/). In Georgia and South Carolina, yield losses in untreated soybean fields averaged 18% and ranged up to 59.6% (Greene et al. 2012, United Soybean Board, Chesterfield, MO; Seiter et al. 2012, J. Econ. Entomol. 106: 1676–1683). Apart from being odoriferous, crushed nymphs have reportedly caused skin rashes, thereby raising health concerns for workers in soybean fields (Ruberson et al. 2013, Appl Entomol Zool. 48: 3–13). Megacopta cribraria is also viewed as a nuisance pest in fall through spring when adults aggregate on or around homes to overwinter, apparently close to kudzu patches (Eger et al. 2010, Insecta Mundi 0121: 1–11; Ruberson et al. 2013). Little is known about the biology and ecology of M. cribraria in North America. Prominently, we do not understand their behavior and population dynamics when host plants are not available, as in the winter. Knowledge of the overwintering behavior and biology of this species could inform surveillance and management. This study was undertaken to identify overwintering refuge areas preferred by M.

Accuracy and reproducibility of patient-specific hemodynamic models of stented intracranial aneurysms: report on the Virtual Intracranial Stenting Challenge 2011.

Validation studies are prerequisites for computational fluid dynamics (CFD) simulations to be accepted as part of clinical decision-making. This paper reports on the 2011 edition of the Virtual Intracranial Stenting Challenge. The challenge aimed to assess the reproducibility with which research groups can simulate the velocity field in an intracranial aneurysm, both untreated and treated with five different configurations of high-porosity stents. Particle imaging velocimetry (PIV) measurements were obtained to validate the untreated velocity field. Six participants, totaling three CFD solvers, were provided with surface meshes of the vascular geometry and the deployed stent geometries, and flow rate boundary conditions for all inlets and outlets. As output, they were invited to submit an abstract to the 8th International Interdisciplinary Cerebrovascular Symposium 2011 (ICS'11), outlining their methods and giving their interpretation of the performance of each stent configuration. After the challenge, all CFD solutions were collected and analyzed. To quantitatively analyze the data, we calculated the root-mean-square error (RMSE) over uniformly distributed nodes on a plane slicing the main flow jet along its axis and normalized it with the maximum velocity on the slice of the untreated case (NRMSE). Good agreement was found between CFD and PIV with a NRMSE of 7.28%. Excellent agreement was found between CFD solutions, both untreated and treated. The maximum difference between any two groups (along a line perpendicular to the main flow jet) was 4.0 mm/s, i.e. 4.1% of the maximum velocity of the untreated case, and the average NRMSE was 0.47% (range 0.28-1.03%). In conclusion, given geometry and flow rates, research groups can accurately simulate the velocity field inside an intracranial aneurysm-as assessed by comparison with in vitro measurements-and find excellent agreement on the hemodynamic effect of different stent configurations.

Field efficacy of a mixture of atoxigenic Aspergillus flavus Link:Fr vegetative compatibility groups in preventing aflatoxin contamination in maize (Zea mays L.)

Competitive exclusion of aflatoxin producers by endemic atoxigenic strains of Aspergillus flavus is a proven tool for aflatoxin management being adapted for use in Africa. Field efficacy of an experimental formulation consisting of four native atoxigenic strains (La3303, La3304, La3279 and Ka16127) was evaluated on maize in 2007 and 2008 in four agroecological zones in Nigeria. The four atoxigenic strains were individually formulated on sterile sorghum grain and subsequently mixed in equal proportions. The blended product was applied on soil (40kg/ha), 2–3weeks before flowering. Grains from treated and untreated fields were analyzed for aflatoxins at harvest and after storage. Proportions of the A. flavus population composed of each of the four applied strains in soil before treatment and in harvested grains were determined using vegetative compatibility analyses. Application of the strain mixture resulted in reduced aflatoxin content and significantly (P<0.05) increased the combined frequencies of the vegetative compatibility groups (VCGs) of the applied strains recovered from the soil and grain. Aflatoxin reductions of 67–95% were associated with a 74–80% combined incidence of the VCGs of the four atoxigenic strains on the treated crops. The applied atoxigenic strains remained with the crop into storage and reduced postharvest increases in contamination. The results suggest that the evaluated multi-strain formulated product has potential to contribute to reduced aflatoxin contamination in Nigeria. This is the first report of a field evaluation of an endemic strain mixture effective at reducing aflatoxin contamination during crop development.