Insecticidal Bt crops and seed treatments represent additional pest management tools for growers, prompting ecological studies comparing their impact on farm system inputs and effects to nontarget ...organisms compared with conventional practices. Using high taxonomic and temporal resolution, we contrast the dominance structure of carabids and dynamics of the most abundant species in maize (both sweet and field corn) agroecosystems using pest management tactics determined by the purchase of seed and application of pyrethroid insecticides. In the seed-based treatments, sweet corn contained Cry1Ab/c proteins, whereas field corn contained the coupled technology of Cry3Bb1 proteins for control of corn rootworm and neonicotinoid seed treatments aimed at secondary soil-borne pests. The insecticide treatments involved foliar pyrethroids in sweet corn and at-planting pyrethroids in field corn. The carabid community, comprised of 49 species, was dominated by four species, Scarites quadriceps Chaudoir, Poecilus chalcites Say, Pterostichus melanarius Illiger, and Harpalus pensylvanicus DeGeer, that each occupied a distinct temporal niche during the growing season. Two species, Pt. melanarius and H. pensylvanicus, exhibited differences between treatments over time. Only H. pensylvanicus had consistent results in both years, in which activity densities in field corn were significantly higher in the control in July and/or August. These results, along with laboratory bioassays, led us to hypothesize that lower adult captures resulted from decrease in prey availability or exposure of H. pensylvanicus larvae to soil-directed insecticides—either the neonicotinoid seed treatment in the transgenic field corn or an at-planting soil insecticide in the conventional field corn.
We confirmed that commercial three- or four-component Spodoptera frugiperda (J.E. Smith) pheromone lures had a high nontarget capture rate for Leucania phragmatidicola Guenée, which compromised ...monitoring efforts in the northeastern United States. We compiled taxonomic features to distinguish L. phragmatidicola from S. frugiperda, and we compared five new lures. S. frugiperda catch specificity was improved by removing (Z)-11-hexadecen-1-ol acetate (Z11–16:Ac), which attracted L. phragmatidicola. Four lures tracked late-season S. frugiperda immigration, but two of these lures also tracked a bivoltine L. phragmatidicola flight with a second generation coincident with S. frugiperda immigration, and one lure attracted the first, but not the second, generation of L. phragmatidicola. In both low- and high-moth flight conditions, two-component lures had low L. phragmatidicola captures (0.5–1.4%), and although lures with more pheromonal components captured more S. frugiperda, they also had a high percentage of capture of L. phragmatidicola (38–48%). We conclude that although two-component lures captured fewer S. frugiperda, their similar temporal pattern, along with the lower level of L. phragmatidicola, makes them useful for development for monitoring programs in the northeastern United States.
Measuring and understanding spatial variation of pests is a fundamental component of population dynamics. The resulting maps can drive spatially variable pest management, which we define as precision ...integrated pest management (IPM). Precision IPM has the potential to reduce insecticide use and slow the rate of resistance development because of the creation of temporally dynamic refuges. This approach to IPM requires sampling in which the objective is to measure spatial variation and map pest density or pressure. Interpolation of spatially referenced data is reviewed, and the influence of sampling design is suggested to be critical to the mapped visualization. Spatial sampling created problems with poor precision and small sample sizes that were partially alleviated with choosing sampling units based on their geostatistical properties, adopting global positioning system technology, and mapping local means. Mapping the probability of exceeding a threshold with indicator kriging is discussed as a decision-making tool for precision IPM. The different types of sampling patterns to deploy are discussed relative to the pest mapping objective.
Fall armyworm Spodoptera frugiperda (J. E. Smith) is a major economic pest throughout the Western Hemisphere of maize, cotton, sorghum, and a variety of agricultural grasses and vegetable crops. ...Previous studies demonstrated extensive annual migrations occurring as far north as Canada from overwintering locations in southern Florida and Texas. In contrast, migratory behavior in the rest of the hemisphere is largely uncharacterized. Understanding the migration patterns of fall armyworm will facilitate efforts to predict the spread of pesticide resistance traits that repeatedly arise in this species and assess the consequences of changing climatic trends on the infestation range. Four independent fall armyworm colonies derived from widely separated populations in Mexico and two field collections were examined for their mitochondrial cytochrome oxidase I (COI) gene haplotypes and compared with other locations. The Mexico populations were most similar in their haplotype profile to those from Texas and South America, but also displayed some distinctive features. The data extend the haplotype distribution map in the Western Hemisphere and confirm that the previously observed regional differences in haplotype frequencies are stable over time. The Mexico collections were associated with haplotypes rarely found elsewhere, suggesting limited migratory interactions with foreign populations, including those in neighboring Texas.
The emission mechanisms of strained InGaN quantum wells (QWs) were shown to vary depending on the well thickness
L and InN molar fraction
x. The QW resonance energy was shifted to lower energy by the ...quantum confined Stark effect (QCSE) due to the internal piezoelectric field,
F
PZ. The absorption spectrum was modulated by QCSE and quantum-confined Franz–Keldysh effect (QCFK) for the wells, in which, for the first approximation, the product of
F
PZ and
L (potential drop across the well) exceeds the valence band discontinuity, Δ
E
V. In this case, dressed holes are confined in the triangular potential well formed at one side of the well. This produces apparent Stokes-like shift (vertical component). The QCFK further modulated the absorption energy for the wells with L greater than the three dimensional free exciton Bohr radius,
a
B. For the wells having high InN content (
F
PZ×
L>Δ
E
V,
Δ
E
C), electron and hole confined levels drop into the triangular potential wells formed at opposite sides of the wells, which reduces the wavefunction overlap. Doping of Si in the barriers partially screens
F
PZ resulting in a smaller Stokes-like shift, shorter recombination decay time, and higher emission efficiency. Si-doping was found to improve the interface quality and surface morphology, resulting in an efficient carrier transfer from high to low bandgap energy portions of the well. Effective in-plane localization of carriers in quantum disk size potential minima, which are produced by nonrandom alloy potential fluctuations enhanced by the large bowing parameter and
F
PZ, produces confined e–h pair whose wavefunctions are still overlapped. Their excitonic features are pronounced provided that
L<
a
B and
F
PZ×
L<
E
V (quantized exciton). Several cw laser wafers exhibit stimulated emission from these energy tail states even at room temperature.
The introduction of avian malaria (Plasmodium relictum) to Hawaii has provided a model system for studying the influence of exotic disease on naive host populations. Little is known, however, about ...the origin or the genetic variation of Hawaii's malaria and traditional classification methods have confounded attempts to place the parasite within a global ecological and evolutionary context. Using fragments of the parasite mitochondrial gene cytochrome b and the nuclear gene dihydrofolate reductase-thymidylate synthase obtained from a global survey of greater than 13 000 avian samples, we show that Hawaii's avian malaria, which can cause high mortality and is a major limiting factor for many species of native passerines, represents just one of the numerous lineages composing the morphological parasite species. The single parasite lineage detected in Hawaii exhibits a broad host distribution worldwide and is dominant on several other remote oceanic islands, including Bermuda and Moorea, French Polynesia. The rarity of this lineage in the continental New World and the restriction of closely related lineages to the Old World suggest limitations to the transmission of reproductively isolated parasite groups within the morphological species.
This literature review and the recommendations therein were prepared for the American Gastroenterological Association Clinical Practice and Practice Economics Committee. The paper was approved by the ...committee on September 27, 1998.
GASTROENTEROLOGY 1999;117:233-254
The International Agency for Research on Cancer (IARC) and the US National Cancer Institute (NCI) have initiated a series of cancer-focused seminars Scelo G, Hofmann JN, Banks RE et al. International ...cancer seminars: a focus on kidney cancer. Ann Oncol 2016; 27(8): 1382–1385. In this, the second seminar, IARC and NCI convened a workshop in order to examine the state of the current science on esophageal squamous cell carcinoma etiology, genetics, early detection, treatment, and palliation, was reviewed to identify the most critical open research questions. The results of these discussions were summarized by formulating a series of ‘difficult questions’, which should inform and prioritize future research efforts.
The degree to which widespread avian blood parasites in the genera Plasmodium and Haemoproteus pose a threat to novel hosts depends in part on the degree to which they are constrained to a particular ...host or host family. We examined the host distribution and host‐specificity of these parasites in birds from two relatively understudied and isolated locations: Australia and Papua New Guinea. Using polymerase chain reaction (PCR), we detected infection in 69 of 105 species, representing 44% of individuals surveyed (n = 428). Across host families, prevalence of Haemoproteus ranged from 13% (Acanthizidae) to 56% (Petroicidae) while prevalence of Plasmodium ranged from 3% (Petroicidae) to 47% (Ptilonorhynchidae). We recovered 78 unique mitochondrial lineages from 155 sequences. Related lineages of Haemoproteus were more likely to derive from the same host family than predicted by chance at shallow (average LogDet genetic distance = 0, n = 12, P = 0.001) and greater depths (average distance = 0.014, n = 11, P < 0.001) within the parasite phylogeny. Within two major Haemoproteus subclades identified in a maximum likelihood phylogeny, host‐specificity was evident up to parasite genetic distances of 0.029 and 0.007 based on logistic regression. We found no significant host relationship among lineages of Plasmodium by any method of analysis. These results support previous evidence of strong host‐family specificity in Haemoproteus and suggest that lineages of Plasmodium are more likely to form evolutionarily–stable associations with novel hosts.
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