Full inversion tillage during pasture renewal to increase soil carbon storage: New Zealand as a case study.

As soils under permanent pasture and grasslands have large topsoil carbon (C) stocks, the scope to sequester additional C may be limited. However, because C in pasture/grassland soils declines with depth, there may be potential to sequester additional C in the subsoil. Data from 247 continuous pasture sites in New Zealand (representing five major soil Orders and ~80% of the grassland area) showed that, on average, the 0.15-0.30 m layer contained 25-34 t ha-1 less C than the top 0.15 m. High-production grazed pastures require periodic renewal (re-seeding) every 7-14 years to maintain productivity. Our objective was to assess whether a one-time pasture renewal, involving full inversion tillage (FIT) to a depth of 0.30 m, has potential to increase C storage by burying C-rich topsoil and bringing low-C subsoil to the surface where C inputs from pasture production are greatest. Data from the 247 pasture sites were used to model changes in C stocks following FIT pasture renewal by predicting (1) the C accumulation in the new 0-0.15 m layer and (2) the decomposition of buried-C in the new 0.15-0.30 m layer. In the 20 years following FIT pasture renewal, soil C was predicted to increase by an average of 7.3-10.3 (Sedimentary soils) and 9.6-12.7 t C ha-1 (Allophanic soils), depending on the assumptions applied. Adoption of FIT for pasture renewal across all suitable soils (2.0-2.6 M ha) in New Zealand was predicted to sequester ~20-36 Mt C, sufficient to offset 9.6-17.5% of the country's cumulative greenhouse gas emissions from agriculture over 20 years at the current rate of emissions. Given that grasslands account for ~70% of global agricultural land, FIT renewal of pastures or grassland could offer a significant opportunity to sequester soil C and offset greenhouse gas emissions.

Beauveria bassiana Culturing and Harvesting for Bioassays With House Flies.

The entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae) has been widely studied against a wide range of arthropod pests, including many of medical and veterinary importance. New investigators must sort through a wide array of published methods for the production, harvest, storage, and bioassay methods for this pathogen. Simplified methods for production of conidia using Sabouraud dextrose agar with yeast (SDYA) plates and two conidial harvesting methods are described. Dry harvesting yields conidia that are ready to incorporate into dusts and food baits, but the fungal product includes mycelial debris that can hamper quantification and introduces variable amounts of unwanted bulk. Wet harvesting with filtration produces a cleaner product that is immediately ready for testing in liquid formulations. Examples of bioassays with house flies are presented that include conidia applied topically to the dorsal thorax for dose-mortality assays and conidial suspensions applied to filter paper disks for concentration mortality assays.

Soil carbon sequestration potential of permanent pasture and continuous cropping soils in New Zealand.

Understanding soil organic carbon (SOC) sequestration is important to develop strategies to increase the SOC stock and, thereby, offset some of the increases in atmospheric carbon dioxide. Although the capacity of soils to store SOC in a stable form is commonly attributed to the fine (clay + fine silt) fraction, the properties of the fine fraction that determine the SOC stabilization capacity are poorly known. The aim of this study was to develop an improved model to estimate the SOC stabilization capacity of Allophanic (Andisols) and non-Allophanic topsoils (0-15 cm) and, as a case study, to apply the model to predict the sequestration potential of pastoral soils across New Zealand. A quantile (90th) regression model, based on the specific surface area and extractable aluminium (pyrophosphate) content of soils, provided the best prediction of the upper limit of fine fraction carbon (FFC) (i.e. the stabilization capacity), but with different coefficients for Allophanic and non-Allophanic soils. The carbon (C) saturation deficit was estimated as the difference between the stabilization capacity of individual soils and their current C concentration. For long-term pastures, the mean saturation deficit of Allophanic soils (20.3 mg C g-1 ) was greater than that of non-Allophanic soils (16.3 mg C g-1 ). The saturation deficit of cropped soils was 1.14-1.89 times that of pasture soils. The sequestration potential of pasture soils ranged from 10 t C ha-1 (Ultic soils) to 42 t C ha-1 (Melanic soils). Although meeting the estimated national soil C sequestration potential (124 Mt C) is unrealistic, improved management practices targeted to those soils with the greatest sequestration potential could contribute significantly to off-setting New Zealand's greenhouse gas emissions. As the first national-scale estimate of SOC sequestration potential that encompasses both Allophanic and non-Allophanic soils, this serves as an informative case study for the international community.

Nontarget effects of aerial mosquito adulticiding with water-based unsynergized pyrethroids on honey bees and other beneficial insects in an agricultural ecosystem of north Greece.

We assessed the nontarget effects of ultra-low-volume (ULV) aerial adulticiding with two new water-based, unsynergized pyrethroid formulations, Aqua-K-Othrine (FFAST antievaporant technology, 2% deltamethrin) and Pesguard S102 (10% d-phenothrin). A helicopter with GPS navigation technology was used. One application rate was tested per formulation that corresponded to 1.00 g (AI)/ha of deltamethrin and 7.50 g (AI)/ha of d-phenothrin. Three beneficial nontarget organisms were used: honey bees (domesticated hives), family Apidae (Apis mellifera L.); mealybug destroyers, family Coccinellidae (Cryptolaemus montrouzieri Mulsant); and green lacewings, family Chrysopidae (Chrysoperla carnea (Stephens)). No significant nontarget mortalities were observed. No bees exhibited signs of sublethal exposure to insecticides. Beehives exposed to the insecticidal applications remained healthy and productive, performed as well as the control hives and increased in weight (25-30%), in adult bee population (14-18%), and in brood population (15-19%).

Droplet sampling of an oil-based and two water-based antievaporant ultra-low volume insecticide formulations using Teflon- and magnesium oxide-coated slides.

We estimated the diameters below which 50% and 90% of the volume of droplets exist (Dv50 and Dv90, respectively) of 1 oil-based (Permanone 30-30) and 2 water-based (AquaReslin, Aqua-K-Othrine) antievaporant aerosols (with the Film Forming Aqueous Spray Technology [FFAST]) using Teflon- and magnesium oxide (MgO)-coated slides and determined whether the aging of the droplets on the slides (up to 60 min) exhibited any significant effect on Dv50 and Dv90 calculations. There were no significant differences in either Dv50 or Dv90 estimates on MgO-coated slides at 0 min and 60 min for all 3 products tested. On Teflon-coated slides, the only product that showed significant difference between 0 min and 60 min in both Dv50 and Dv90 estimates was Aqua-K-Othrine, perhaps due to a difference in formulation components. Specifically, both values corresponding to Dv50 and Dv90 at 60 min decreased by approximately 50% when compared to the values at 0 min. For the other 2 products, AquaReslin and Permanone, aging of droplets on Teflon up to 60 min did not have any significant effect on Dv50 and Dv90 values. To further investigate the behavior of Aqua-K-Othrine droplets on Teflon-coated slides we observed the droplets immediately after spraying and at 10-min intervals under different conditions of temperature and humidity. The majority of the shrinkage occurred within the 1st 10 min after impaction on the slides under all conditions tested. So in most field situations where slides are read several hours or days after collection, this shrinkage would not be observed. The MgO-coated slides should be the preferred field method for sampling droplets of Aqua-K-Othirne with the FFAST antievaporant technology.

[The workings of a Darwinist brain: Guedes Cabral and the evolutionism ofFunções do cérebro(1876)]. / As funções de um cérebro darwinista: Guedes Cabral e o evolucionismo de Funções do cérebro (1876).

The book Funções do cérebro (Workings of the brain), by physician Domingos Guedes Cabral, is recognized as one of the first Brazilian works to defend Darwinist theories. In light of the need for more studies on the reception of evolutionism in Brazil, the article investigates this book in an effort to reveal how Guedes Cabral used evolutionism in his argumentation and to reveal the purpose of his arguments within a historical context. Findings indicate that Guedes Cabral relied on evolutionism as part of both an ideological project and an incipient eugenic theory, later developed in the early twentieth century.

Caragana korshinskii Kom. plantation reduced soil aggregate stability and aggregate-associated organic carbon on desert steppe.

BACKGROUND: After implementing of the "Grain-for-Green" project, Caragana korshinskii Kom. has been widely planted in China's arid regions. Although natural restoration grassland and artificial Caragana plantations measures have long been focuses in carbon research, the combined influence of natural restoration grassland and artificial Caragana plantation measures on aggregate stability and the aggregate-associated organic carbon (OC) remains unclear. METHOD: We selected natural grassland (NG) and three different densities of Caragana plantations (high planting density, HG; middle planting density, MD; low planting density, LD) on desert steppe. The soil aggregate distribution and stability index such as fractal dimension (D), mean weight diameter (MWD), geometric mean diameter (GMD), percentage of aggregation destruction (PAD), as well as aggregate-associated OC concentration and stock were measured. RESULTS: Results shows that the soil aggregates were primarily macroaggregates (>2 mm) and mesoaggregates (0.25-2 mm) under dry sieving while microaggregates (<0.25 mm) were preponderant under wet sieving (more than 57%). Overall, compared with Caragana plantations, the MWD (4.43 and 4.51 mm) and GMD (1.72 and 1.83 mm) were both highest in two soil layers under the NG and the D (2.77 and 2.71) was lowest. Compared with the NG, the aggregate-associated OC stocks in the 0-40 cm depths in the LD, MD, and HD decreased by 41.54%, 46.93%, and 42.03%, respectively. SOC stock was mainly concentrated in the soil aggregate with sizes of >2 mm and <0.25 mm. These results suggested that natural grassland restoration measures could improve the soil aggregate stability and aggregate-associated OC concentration better than Caragana plantation restoration measures, which NG may be optimal for increasing carbon sequestration and stabilizing soil aggregates on desert steppe.

Biochar impacts on soil chemical properties, greenhouse gas emissions and forage productivity: A field experiment.

Biochar is a promising alternative to agricultural productivity and climate change mitigation. However, quantitative data are needed to better understand the productivity and greenhouse gas (GHG) emissions from agricultural fields amended with biochar. To assess the impacts of the four biochars on soil properties, forage productivity, and GHG emissions, a 1-year field experiment was conducted in a Humic Haploxerands (Andisol). Three manure-derived biochars and one wood residue biochar (all pyrolyzed at 550 °C) were applied at rates of 1% (equivalent to 11 t ha-1) in two parallel and independent experiments. The changes in (i) soil chemical properties and yield of Sorghum sudangrass (S. bicolor×S. bicolor var. Sudanese) and (ii) soil CO2 and N2O emissions were monitored. Two controls, with and without NPK, were included. The added amendments produced from residues of poultry and pig systems increased soil pH by 0.73 and 0.19 units, respectively. Increased sorghum yield were associated with fertilizer and the liming potential of the added biochar. Soil total carbon (TC) increased with the addition of different biochars, especially during the wood biochar treatment. Biochar application, regardless of the feedstock, had no significant impact on the cumulative soil CO2 emitted after a year. Soil N2O fluxes decreased (23%-50%) in treatments containing biochars with low mineral N contents and high C stability (i.e., low H:OC and Cox:TC ratios). NPK treatment resulted in the highest N2O emissions. Wood residue-derived biochar has a great potential in mitigating climate change, reducing soil N2O emissions, and promoting soil C storage. Manure-derived biochars could be instrumental in circular economy livestock systems, where pyrolyzed animal manure can satisfy the demand for nutrients and/or liming of Andisols under sustainable forage models.

Kneallhazia carolinensae sp. nov., a microsporidian pathogen of the thief ant, Solenopsis carolinensis.

A new species of microsporidia is described from adults of the thief ant, Solenopsis carolinensis, collected in Florida, USA. Morphological and genetic characterization of this new species showed that it is most closely related to the genus Kneallhazia and is therefore formally designated, Kneallhazia carolinensae sp. nov. Masses of ovoid, binucleate spores were localized to fat body of adult workers and measured 6.2±0.1×3.1±0.1 µm (fresh) and 6.0±0.1×3.4±0.1 µm (fixed). These spores were in direct contact with the cell cytoplasm and contained an isofilar polar filament with 12-15 coils. Blastn analysis revealed that the K. carolinensae 16S rDNA sequence exhibited 91% identity with the 16S rDNA gene of K. solenopsae. The morphological and sequence data support the conclusion that K. carolinensae is a novel microsporidian species distinct from K. solenopsae.

Efficacy of aerial ultra-low volume applications of two novel water-based formulations of unsynergized pyrethroids against riceland mosquitoes in Greece.

We assessed the efficacy of ultra-low volume aerial adulticiding with 2 new water-based, unsynergized formulations of Aqua-K-Othrin (2% deltamethrin) and Pesguard S102 (10% d-phenothrin) against the riceland mosquitoes of Greece. A helicopter with Global Positioning System (GPS) navigation, real-time weather recording, and spray dispersal modeling (AgDISP) was utilized to accurately treat the experimental blocks by adjusting spray line positions to changing meteorological conditions. Two application rates were applied per formulation that corresponded to 0.75 and 1.00 g AI/ha of deltamethrin and 7.50 and 10.00 g AI/ha of d-phenothrin. The mosquitoes used for the trials were the main nuisance species found in rice field areas of Thessaloniki, which were primarily Aedes caspius, followed by Culex modestus and Anopheles sacharovi. Overall mean mortality of caged mosquitoes was 69.2% and 64.8% for deltamethrin and d-phenothrin, respectively. Mean population decrease in wild mosquito populations within the treatment areas was 76.5% and 78% for deltamethrin and d-phenothrin, respectively. The AgDISP dispersal model, coupled with GPS navigation and real-time weather recording, enabled accurate placement of the spray cloud such that the majority of the treatment area received sufficiently high droplet densities to result in uniform caged-mosquito mortality across all sampling sites.

Influence of resin matrix on the rheology, translucency, and curing potential of experimental flowable composites for bulk-fill applications.

OBJECTIVE: To propose monomer formulations that show an optimal degree of conversion as a function of depth for bulk-fill applications. METHODS: Four resin blends were formulated with methacrylate-based monomers: BisGMA + TEGDMA (control); BisEMA + BisGMA + TEGDMA (BisEMA-based); UDMA + BisGMA + TEGDMA (UDMA-based) and BisEMA + UDMA + BisGMA + TEGDMA (BisEMA + UDMA-based). For each material, a photoinitiating system and silanized filler particles were added. The rheological analyses were performed with a rotational rheometer using the cone/plate geometry. CIELab coordinates were assessed over black and white backgrounds using a bench spectrophotometer (SP60, X-Rite) to calculate the translucency parameter (TP) for samples with 0.5, 4, and 6 mm thickness. The degree of CC conversion (DC) was determined by infrared spectroscopy (FTIR/ATR) at 0.05 mm (top), 4, and 6 mm depths (bottom), and the bottom-to-top ratio was considered. A broad spectrum-based LED was used for light activation. Analysis of variance and Tukey's test (95%) were performed on the results. RESULTS: The materials tested showed pseudoplastic and thixotropic behavior and a predominance of viscous effects over elastics. The control resin yielded the lowest viscosity for the entire shear rate investigated, followed by the BisEMA-based, BisEMA + UDMA-based, and UDMA-based group, which had the highest viscosity. The UDMA-based material showed the lowest TP as a function of thickness. Both the materials' formulations and depths significantly influenced the DC. The UDMA-based group promoted the highest DC ​​on the top (71 ± 1%) and 4 mm depth (68 ± 1%) but exhibited lower bottom-to-top DC ratio. The BisEMA + UDMA-based material promoted the highest bottom-to-top DC ratio at 4 mm (99%) and 6 mm (97%). SIGNIFICANCE: The resin matrix interferes in the rheological behavior, translucency parameter, and polymerization capacity as a function of depth. The material formulated with the addition of UDMA and BisEMA demonstrated the highest curing potential as a function of depth and can be useful for bulk-fill applications.

Effect of soil cadmium on root organic acid secretion by forage crops.

The two forage species used in New Zealand pastoral agricultural systems, chicory (Cichorium intybus) and plantain (Plantago lanceolata) show differential ability to absorb and translocate cadmium (Cd) from roots to shoots. Chicory can accumulate Cd from even low Cd soils to levels that might exceed regulatory guidelines for Cd in fodder crops and food. Chicory and plantain were grown in soil-filled rhizocolumns under increasing Cd levels (0 (Control), 0.4, 0.8 and 1.6 mg Cd/kg soil) for 60 days and showed variable secretion of oxalic, fumaric, malic and acetic acids as a function of Cd treatment. Plant roots secrete such Low Molecular Weight Organic Acids into the rhizosphere soil, which can influence Cd uptake. Chicory showed significantly (P < 0.05) lower secretion of fumaric acid, and higher secretion of acetic acid than plantain at all Cd treatments. We propose that the significant secretion differences between the two species can explain the significantly (P < 0.05) higher shoot Cd concentration in chicory for all Cd treatments. Understanding the mechanism for increased uptake in chicory may lead to breeding or genetic modification which yield low Cd uptake cultivars needed to mitigate the risk of Cd accumulation in pastoral agricultural food chains from this increasingly important fodder crop.

Underwater endoscopic mucosal resection of adenomas and colorectal serrated lesions: a prospective clinical study.

BACKGROUND: Underwater endoscopic mucosal resection (UEMR) without submucosal injection has been described as an alternative technique to the endoscopic resection of adenomas and colorectal serrated lesions. We aimed to assess the feasibility, safety, and efficacy of UEMR in a Brazilian setting. METHODS: This was a prospective observational study of consecutive patients who underwent UEMR between January and July 2019, in a single tertiary care center. Inclusion criteria were lesions without endoscopic stigmata of deep submucosal invasion in patients referred for endoscopic resection of colorectal adenomas, and serrated lesions detected in a previous colonoscopy. The following features were assessed: complete resection rate, en bloc resection rate, resection time, adverse events, and resection infeasibility. RESULTS: A total of 36 patients underwent UEMR for 51 colorectal lesions. The mean/median lesion size was 16.24/13 mm and the mean/median resection time was 16.97/9.19 min. Histopathology revealed the following: tubular adenoma (43.1%), tubulovillous adenoma (13.7%), serrated lesions (41.2%), and intramucosal adenocarcinoma (2%). Complete resection was achieved in 86.3% of cases; 52.9% of the lesions were removed en bloc, while 47.1% were resected in a piecemeal fashion. UEMR was feasible in 96.1% of cases and failed on 2 occasions, requiring conversion to standard endoscopic mucosal resection. Minor intraoperative bleeding occurred in 5 patients (9.8%) and only 1 presented with delayed bleeding (2%), all controlled endoscopically. CONCLUSION: UEMR for removal of adenomas and colorectal serrated lesions was demonstrated to be feasible, safe and effective.

Effect of population structure and size on aggregation behavior of Cimex lectularius (Hemiptera: Cimicidae).

The bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), occurs in aggregations until the conditions are no longer beneficial, leading to dispersal. Active and passive bed bug dispersal causes migrations from main aggregations either within a room, from room to room within a building, or from building to building. Because bed bug movement is an important factor in the spread of infestations, we wanted to determine how population structure and size affect bed bug aggregations. Engorged bed bugs were placed in glass petri dish arenas at varying densities, sex ratios, and population compositions. Nymphs had a high tendency to aggregate, varying between 94 and 98%, and therefore were not the likely dispersal stage of the bed bug. At densities of 10 and 40 adults at a 1:1 sex ratio, there were significantly more lone females than lone males. When the population composition was varied, the percentage of lone females was significantly higher than that of males and nymphs at population compositions of 40 and 80% adults. When the sex ratio of adults was varied, there were significantly more lone females than males in arenas with 20, 50, and 80% males. Females, being found away from aggregations significantly more often than any other life stage, are potentially the dispersal stage of the bed bug. Active female dispersal away from main aggregations can potentially lead to treatment failures and should be taken into account when using control methods.

Toxicities of 31 volatile low molecular weight compounds against Aedes aegypti and Culex quinquefasciatus.

This research studied 31 volatile compounds for indoor control of the medically important mosquitoes Aedes aegypti L. and Culex quinquefasciatus Say. Only adult female mosquitoes were tested. The test compounds were from six families that included five heterobicyclics, eight formate esters, formic acid (a hydrolyzed metabolite of formate esters), eight acetate esters, four propionate esters, three butyrate esters, and two valerate esters. Also, the organophosphate compound dichlorvos (DDVP) was tested as a positive control. Cx. quinquefasciatus was generally more susceptible than Ae. aegypti. Cx. quinquefasciatus was most susceptible to a subset of heterobicyclics and formate esters (rank: n-butyl formate > hexyl formate = dihydrobenzofuran = menthofuran = heptyl formate = ethyl formate). Ae. aegypti was most susceptible to a subset of formate esters (rank: methyl > n-butyl > propyl = ethyl = hexyl). The most active materials against both species had LC50s of 0.4-1 mg active ingredient per 0.5 liter of air volume (0.8-2 mg/liter), which is 50- to 60-fold less toxic than dichlorvos (an organophosphate insecticide that is being phased out from indoor use). In relation to Drosophila melanogaster Meigen, both mosquito species were generally more susceptible to formate esters but more tolerant of heterobicyclics. Generally, the most toxic compound against all dipterans tested to date is n-butyl formate, whereas menthofuran is additionally toxic against Cx. quinquefasciatus and D. melanogaster. Finally, the toxicity differences between species point to the potential for differential toxicity among mosquito general/species, suggesting that further studies of a number of mosquito species might be warranted.

Vapor toxicity of three prototype volatile insecticidal compounds to house fly (Diptera: Muscidae).

Vapor toxicities of two prototype formate esters, ethylene glycol di-formate (EGDF) and heptyl formate, and the prototype heterobicyclic menthofuran were determined against laboratory-reared adult house flies, Musca domestica L. (Diptera: Muscidae). Toxicities were compared between house flies and other dipteran species tested previously. The organophosphate fumigant insecticide dichlorvos (DDVP) was used as a positive control. Although less toxic than DDVP, all three prototype compounds were toxic to house flies. Most toxic was menthofuran (LC50 = 3.70 mg/liter air), followed by EGDF (LC50 = 9.27 mg/liter air) and heptyl formate (LC50 = 32.62 mg/liter air). The toxicity of menthofuran when applied after piperonyl butoxide increased 1.5-fold. The toxicities of heptyl formate and EGDF when applied after S,S,S-tributyl phosphorotrithioate decreased by 1.5- and 2-folds, respectively. These results are slightly different from results obtained for other dipterans, further supporting previous hypotheses that toxicity may have some species specificity. Ceramic porous rods impregnated with heptyl formate were used to evaluate the effectiveness of controlled vapor release for a single dose of heptyl formate against house flies. Controlled vapor release ofheptyl formate can be used successfully to provide prolonged house fly mortality. Even though the prototype compounds did not exhibit toxicity as high as that of DDVP, their toxicities to dipterans, along with their reduced mammalian toxicities relative to DDVP, make them potential DDVP replacement candidates.

Lethal effects of heat and use of localized heat treatment for control of bed bug infestations.

Bed bugs, Cimex lectularius L., hide in cracks and crevices in furniture and are difficult to control. The bed bug thermal death kinetics were examined to develop a heat treatment method to eliminate bed bug infestations in room contents. High temperatures caused temporary immobilization (knockdown) of bed bugs even with exposures that did not have lethal effects. Exposure of bed bug adults to 39 degrees C for 240 min caused no mortality; however, as temperatures increased from 41 to 49 degrees C, exposure times that caused 100% mortality decreased. The temperature difference to provide a 10-fold change in the mortality was estimated at 4 degrees C, and the estimated activation energy (EA) was between 484 and 488.3 kJ/mol. This demonstrates that bed bugs are not more resistant or susceptible to changes in temperature than other tested insects and that the temperatures needed to kill bed bugs are relatively low. In room treatment tests, heat treatment times varied from 2 to 7 h with complete mortality of exposed bed bugs within the treatment envelope created by surrounding the treated furniture with polystyrene sheathing boards. Containment and circulation of heat around the treated material were crucial factors in an efficient heat treatment for bed bug control. The room floor material greatly affected containment of the heat. The tested method for limited heat treatment of furniture and other room contents required equipment costing less than US$400 and provided opportunity for residual pesticide application around the room with minimal disruption in use of treated room.

Comparative Quantification of Trail-Following Behavior in Pest Ants.

A comparison of trail-following movement parameters of six major urban pest ants, Nylanderia fulva (Forel) (Hymenoptera: Formicidae), Pheidole megacephala, Linepithema humile (Mayr), Solenopsis invicta Buren, Paratrechina longicornis (Forel), and Technomyrmex albipes (Smith) demonstrated several differences in velocity of movement, amplitude of the deviations from a marked trail, percent fidelity to the trail, number of curves per unit of trail, and trail-following accuracy. Paratrechina longicornis and N. fulva had the largest deviations from the marked trails and moved three times faster (25-30 mm/s) along the trail than the slowest ant, S. invicta (< 10 mm/s), with other ants following between these extremes. Species differences in relation to going toward or returning from food were observed in a few cases, especially with Pa. longicornis for which velocity, amplitude, and trail fidelity differed between the foraging and return trails. Quantification of ant trail-following movement parameters can be useful in understanding the mechanics of ant movement and may be important in testing specific strategies and products that disrupt trail-following behavior.

Factors Affecting Short-Range Host-Seeking for the Yellow Fever Mosquito (Diptera: Culicidae).

Understanding short-range cues (e.g., host odorants, heat, moisture) of host-seeking female Aedes aegypti L. is very important for attempts to reduce mosquito bites, to complement current control strategies, and to develop potential spatial repellents. We investigated behavior under semi-field conditions utilizing a new portable uni-port taxis box with a caged chicken host. The combined influences of airflow regimes (0, 1.5, 3, 5, and 6 m/s), distance from host odor (10, 50, 100 cm), host-odor confinement (partial confinement/unconfined), and foraging periodicity (day/evening) were studied. Statistical regression analysis was used to delineate the significant factors that predict upwind flight behavior and short-range source location. Almost 15% of host-seeking Ae. aegypti were activated by an unconfined chicken odor in still air. This was double the number of attracted mosquitoes to confined host odor. The maximum behavioral response was reported with airflow of 5 m/s during daytime (76.7% ± 2.85) at a distance of 10 (70.7% ± 2.47) and 50 cm (56.7% ± 8.88). However, airflow of 6 m/s activated host-seeking orientation during evening assays. The host-seeking response between indoor and outdoor experiments was not significantly different and demonstrated the reliability of the portable taxis box in evaluating mosquito short-range behavioral response toward hosts.

Mosquitocidal Chips Containing the Insect Growth Regulator Pyriproxyfen for Control of Aedes aegypti (Diptera: Culicidae).

Aedes aegypti were exposed to water treated with mosquitocidal chips containing the insecticide pyriproxyfen in a polymer formulation. Chips were tested under different conditions; different water volumes, in containers made of different material, and in water with different levels of organic matter. Treated chips caused 100% mortality of Ae. aegypti during their pupal stage independent of size or type of container, and the mount of organic matter contained in the water to which the mosquito larvae were exposed. When mosquitocidal chips were used in >25% of the oviposition containers within their cages, there was a significant control of the mosquito populations. Mosquitocidal chips worked in different environments, caused significant mosquito population decreases, and were effective in controlling Ae. aegypti.