Soil and Foliar Arthropod Abundance and Diversity in Five Cropping Systems in the Coastal Plains of North Carolina.

Soil and foliar arthropod populations in agricultural settings respond to environmental disturbance and degradation, impacting functional biodiversity in agroecosystems. The objective of this study was to evaluate system level management effects on soil and foliar arthropod abundance and diversity in corn and soybean. Our field experiment was a completely randomized block design with three replicates for five farming systems which included: Conventional clean till, conventional long rotation, conventional no-till, organic clean till, and organic reduced till.

Impact of Location, Cropping History, Tillage, and Chlorpyrifos on Soil Arthropods in Peanut.

Demand for agricultural production systems that are both economically viable and environmentally conscious continues to increase. In recent years, reduced tillage systems, and grass and pasture rotations have been investigated to help maintain or improve soil quality, increase crop yield, and decrease labor requirements for production. However, documentation of the effects of reduced tillage, fescue rotation systems as well as other management practices, including pesticides, on pest damage and soil arthropod activity in peanut production for the Mid-Atlantic US region is still limited.

The Influence of Habitat Manipulations on Beneficial Ground-Dwelling Arthropods in a Southeast US Organic Cropping System.

Habitat manipulations, intentional provisioning of natural vegetation along crop edges, have been shown to enhance beneficial epigaeic invertebrate activity in many agricultural settings, but little research has been conducted on this practice in the southeast United States. We conducted a field-scale study to determine if habitat manipulations along the field edges of an organic crop rotation increase the activity-density of beneficial ground-dwelling invertebrates. Pitfall traps were used to collect micro and macro ground-dwelling organisms in nine organic crop fields (three each of maize, soybeans, and hay; 2.

St. Augustine grass germplasm resistant to Blissus insularis (Hemiptera: Blissidae).

St. Augustine grass (Stenotaphrum secundatum (Walter) Kuntze) is an economically important turfgrass in the southeastern United States. However, this turf species is prone to southern chinch bug, Blissus insularis Barber (Heteroptera: Blissidae) outbreaks.

Contact toxicities of anuran skin alkaloids against the fire ant (Solenopsis invicta).

Nearly 500 alkaloids, representing over 20 structural classes, have been identified from the skin of neotropical poison frogs (Dendrobatidae). These cutaneous compounds, which are derived from arthropod prey of the frogs, generally are believed to deter predators. We tested the red imported fire ant (Solenopsis invicta) for toxicosis following contact with 20 alkaloids (12 structural classes) identified from dendrobatids or other anurans.

Arabidopsis thaliana resistance to insects, mediated by an earthworm-produced organic soil amendment.

Background: Vermicompost is an organic soil amendment produced by earthworm digestion of organic waste. Studies show that plants grown in soil amended with vermicompost grow faster, are more productive and are less susceptible to a number of arthropod pests. In light of these studies, the present study was designed to determine the type of insect resistance (antixenosis or antibiosis) present in plants grown in vermicompost-amended potting soil.

Multipartite symbioses among fungi, mites, nematodes, and the spruce beetle, Dendroctonus rufipennis.

The spruce beetle, Dendroctonus rufipennis, is an eruptive forest pest of significant economic and ecological importance. D. rufipennis has symbiotic associations with a number of microorganisms, especially the ophiostomatoid fungus Leptographium abietinum.

Phloem alkaloid tolerance allows feeding on resistant Lupinus angustifolius by the aphid Myzus persicae.

We examined the hypothesis that the polyphagous green peach aphid (Myzus persicae) shows clone-specific adaptation to the narrow-leafed lupin (Lupinus angustifolius) containing toxic quinolizidine alkaloids. We compared the performance of a lupin-feeding clone of M. persicae from Western Australia to that of nine clones of the same species collected from eastern Australian locations, where narrow-leafed lupins rarely occur.

Compatible and incompatible Xanthomonas infections differentially affect herbivore-induced volatile emission by pepper plants.

Recent studies have alerted us to the potential for conflicts between pathogen- and herbivore-induced plant defenses. The lack of studies on the induced chemical changes that simultaneous insect and pathogen attacks have on the host plant has become apparent. In the present study, we found that pepper plant volatile profiles can be differentially induced by compatible and incompatible bacterial infection and beet armyworm (BAW) damage when applied alone or in combination upon the same host.

Differential volatile emissions and salicylic acid levels from tobacco plants in response to different strains of Pseudomonas syringae.

Pathogen-induced plant responses include changes in both volatile and non-volatile secondary metabolites. To characterize the role of bacterial pathogenesis in plant volatile emissions, tobacco plants, Nicotiana tabacum L. K326, were inoculated with virulent, avirulent, and mutant strains of Pseudomonas syringae.

Simultaneous quantification of jasmonic acid and salicylic acid in plants by vapor-phase extraction and gas chromatography-chemical ionization-mass spectrometry.

Jasmonic acid and salicylic acid represent important signaling compounds in plant defensive responses against other organisms. Here, we present a new method for the easy, sensitive, and reproducible quantification of both compounds by vapor-phase extraction and gas chromatography-positive ion chemical ionization-mass spectrometry. The method is based on a one-step extraction, phase partitioning, methylation with HCl/methanol, and collection of methylated and, thus, volatilized compounds on Super Q filters, thereby omitting further purification steps.

In vivo volatile emissions from peanut plants induced by simultaneous fungal infection and insect damage.

Peanut plants, Arachis hypogaea, infected with white mold. Sclerotium rolfsii, emit a blend of organic compounds that differs both quantitatively and qualitatively from the blend emitted from plants damaged by beet armyworm (BAW; Spodoptera exigua) larvae or from uninfected, undamaged plants. Attackby BAW induced release of lipoxygenase products (hexenols, hexenals, and hexenyl esters), terpenoids, and indole.