Publications by authors named "John S Armstrong"

The hedgehog grain aphid (HGA), Passerini (Hemiptera: Aphididae), is a cereal pest in many regions of the world. It was first documented in the United States in 2007, and it has a range that appears to be expanding. Understanding the effects of temperature and the host plant on HGA development, survival, and reproduction is crucial for understanding its population dynamics, potential distribution, and management strategies.

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Pollinators are declining globally, potentially reducing both human food supply and plant diversity. To support pollinator populations, planting of nectar-rich plants with different flowering seasons is encouraged while promoting wind-pollinated plants, including grasses, is rarely recommended. However, many bees and other pollinators collect pollen from grasses which is used as a protein source.

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(Hemiptera: Aphididae), are an economically important pest to sorghum in the Americas. Previous studies have found that a super-clone that belongs to multilocus lineage (MLL)-F predominated in the U.S.

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The sugarcane aphid Melanaphis sacchari (Zehnter) (Hemiptera: Aphididae) has emerged as a potential threat to sorghum (Sorghum bicolor (L.) Moench) production in the United States. Since the late summer of 2013, finding and advancing M.

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A phylogeny has been calculated by maximum likelihood comparisons of the concatenated consensus protein sequences of 29 tobamoviruses shown to be non-recombinant. This phylogeny has statistically significant support throughout, including its basal branches. The viruses form eight lineages that are congruent with the taxonomy of the hosts from which each was first isolated and, with the exception of three of the twenty-nine species, all fall into three clusters that have either asterid or rosid or caryophyllid hosts (i.

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Most of the genomic sequence of Chara australis virus (CAV), previously called Chara corallina virus, has been determined. It is a ssRNA molecule of 9065 nt with at least four ORFs. At its 5' end is an ORF encoding a protein of 227 kDa, distantly homologous to the multifunctional replicases of benyviruses and rubiviruses.

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The swine-origin influenza A (H1N1) virus that appeared in 2009 and was first found in human beings in Mexico, is a reassortant with at least three parents. Six of the genes are closest in sequence to those of H1N2 'triple-reassortant' influenza viruses isolated from pigs in North America around 1999-2000. Its other two genes are from different Eurasian 'avian-like' viruses of pigs; the NA gene is closest to H1N1 viruses isolated in Europe in 1991-1993, and the MP gene is closest to H3N2 viruses isolated in Asia in 1999-2000.

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Fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), infestations in most of North America north of Mexico arise from annual migrations of populations that overwinter in southern Texas and Florida.

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Studies on insect dispersal and other behaviors can benefit from using markers that will not alter flight and fitness. Rare earth elements, such as samarium (Sm), have been used as ingested markers of some insects and detected using neutron activation analysis (NAA). In this study, samarium nitrate hexahydrate was mixed into artificial diet for boll weevils, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), at different dosages and in water used to irrigate cotton, Gossypium hirsutum L.

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Background: Most current DNA diagnostic tests for identifying organisms use specific oligonucleotide probes that are complementary in sequence to, and hence only hybridize with the DNA of one target species. By contrast, in traditional taxonomy, specimens are usually identified by 'dichotomous keys' that use combinations of characters shared by different members of the target set. Using one specific character for each target is the least efficient strategy for identification.

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Plant damage and yield response to the Russian wheat aphid, Diuraphis noxia (Mordvilko), were evaluated on a susceptible (TAM 107) and a resistant (RWA E1) winter wheat, Triticum aestivum L., in three Colorado locations in the 1993 and 1994 crop years. Russian wheat aphid was more abundant on TAM 107 than on RWA E1.

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