Foliar residue dynamics of azadirachtins following direct stem injection into white and green ash trees for control of emerald ash borer

BACKGROUND: Azadirachtins are natural insecticides derived from the neem tree. The emerald ash borer (EAB) is an exotic invasive insect pest that infests various ash tree species and has the potential for significant economic, aesthetic and ecological impacts throughout North America. The initial translocation and foliar residue dynamics of azadirachtins were examined following direct injection into white and green ash trees growing in urban scenarios as a potential control for EAB. RESULTS: Substantial concentrations of azadirachtins A and B [mean maxima > 0.98 mg kg^?1 fresh weight (f.w.)] were observed within 2 days of injecting a specifically designed formulation of azadirachtins. Foliar residues declined exponentially through time, with half‐life estimates ranging from 5.1 to 12.3 days. At the time of leaf senescence, foliar residue levels approximated 0.01 mg kg^?1 f.w., strongly mitigating the potential effects of non‐target biota in soil or aquatic compartments. CONCLUSION: The magnitude and duration of exposures observed in this field study were considered to be above the thresholds required for biological effectiveness against both larval and adult life stages of EAB. Results support the use of azadirachtins as an environmentally acceptable systemic insecticide for control of EAB and protection of high‐value ash trees in urban environments. Copyright © 2011 Society of Chemical Industry     

Laboratory and field comparisons of insecticides to reduce infestation of Drosophila suzukii in berry crops

BACKGROUND: The spotted wing Drosophila, Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae), is an invasive pest of small‐fruit crops. Unlike most other Drosophila, this insect is able to oviposit into and damage ripe and ripening fruit, making it unmarketable. Because this is a new pest in the United States, it is necessary to identify registered insecticides to manage this insect effectively in conventional and organic production systems. RESULTS: The present laboratory bioassays and field trials identified a number of insecticides representing various modes of action that are effective in controlling D. suzukii. Products that performed well in the laboratory bioassay also performed well in the field, indicating that screening of new chemistries in the laboratory is a worthy exercise. Field application of pyrethoids, organophosphates or spinosyns provided 5–14 days of residual control of D. suzukii. The efficacy of the neonicotinoids as adulticides was not satisfactory compared with the other contact‐mode‐of‐action chemistries. Based on the zero tolerance by the small‐fruit industry and the individual effects mentioned above, neonicotinoids are not currently recommended for D. suzukii management. CONCLUSIONS: There are effective insecticides registered for controlling D. suzukii infestations in susceptible small‐fruit crops. Copyright © 2011 Society of Chemical Industry     

Global forest systems: An uncertain response to atmospheric pollutants and global climate change?

Forest systems cover more than 4.1×10⁹ ha of the Earth's land area. The future response and feedbacks of forest systems to atmospheric pollutants and projected climate change may be significant. Boreal, temperate and tropical forest systems play a prominent role in carbon (C), nitrogen (N) and sulfur (S) biogeochemical cycles at regional and global scales. The timing and magnitude of future changes in forest systems will depend on environmental factors such as a changing global climate, an accumulation of CO₂ in the atmosphere, and increase global mineralization of nutrients such as N and S. The interactive effects of all these factors on the world's forest regions are complex and not intuitively obvious and are likely to differ among geographic regions. Although the potential effects of some atmospheric pollutants on forest systems have been observed or simulated, large uncertainty exists in our ability to project future forest distribution, composition and productivity under transient or nontransient global climate change scenarios. The potential to manage and adapt forests to future global environmental conditions varies widely among nations. Mitigation practices, such as liming or fertilization to ameliorate excess NO_x or SO_x or forest management to sequester CO₂ are now being applied in selected nations worldwide.The U.S. Government's right to a non-exclusive, royalty free licence in and to any copyright is acknowledged.     

Analysis of lidocaine and its major metabolite, monoethylglycinexylidide, in elk velvet antler by liquid chromatography with UV detection and confirmation by electrospray ionization tandem mass spectrometry

A sensitive liquid chromatographic (LC) method with UV detection was developed for the determination of residues of lidocaine (LID) and its major metabolite, monoethylglycinexylidide (MEGX), in elk velvet antler. The drugs were extracted from alkaline velvet antler homogenates, cleaned up on a C(18) solid-phase extraction cartridge, and separated on an Inertsil ODS-3 (3.0 x 250 mm, 5 microm) column using an isocratic mobile phase made up of 0.05 M phosphate buffer (pH 4.0)/acetonitrile (88:12, v/v) at a flow rate of 1.0 mL/min. The limits of quantification for LID and its major metabolite, MEGX, were 10 and 20 ng/g, respectively. The method was validated and used to measure the concentration of residues of LID and MEGX in elk velvet antlers harvested after either LID anesthesia or application of a drug-free control method (electro-anesthesia, EA). No LID or MEGX residues were detected in any of the antlers harvested after EA application. No MEGX residues were detected in any of the velvet antlers harvested after LID application, but residues of LID ranging in concentration from 68 to 4300 ng/g were detected in the three sections of the velvet antlers harvested after LID administration. LC-tandem mass spectrometry was used to confirm the presence of lidocaine detected in the velvet antlers.     

Urease activity in two cultivated and non-cultivated arid soils

Summary Since urease activity in soil is believed to be relatively constant, the present study was designed to examine the effects of incubation, soil depth and the effect of cultivation on the persistence of urease activity in arid soils. Two soils were used, a Harkey (coarse, silty, mixed, calcareous, thermic, Typic Torrifluvent) and a Saneli (Clayey over sandy skeletal, montmorillonitic, calcareous, Vertic Torrifluvent), each consisting of a cultivated field and a non-cultivated roadbed site. Urease activity was much lower and more varable in the roadbed soils (40 years without cultivation) than in the cultivated field soils. Pre-incubation for 24 h with urea (with toluene) and without urea (without toluene) greatly reduced the total urease activity in all cases in relation to cell free urease activity (with toluene). Urease activity in the two field soils decreased slightly with profile depth but the decrease was greatest below the plow depth (33 cm). Protease activity or some inactivation processes must have lowered the urease content since there was substantially reduced urease activity after most pre-incubations. The extent of the urease activity decrease was so great that the addition of urea would have been required to increase the production of urease enzyme.     

The potential acidity associated with dews,frosts, and fogs

Acidity associated with special meteorological events such as dews, frosts, and fogs may cause significant environmental effects ranging from increased leaching of plant metabolites to material corrosion. In addition, dews, frosts and fogs occur with much greater frequencies than rain or snow in most areas. Due to these facts, a theoretical study was conducted to determine the potential acidity associated with these events. Results from this study showed the potential acidity associated with these events to be significant. Values of fog pH are extremely sparse, but indicate that they are slightly acidic. However, these experiments have probably under-estimated the actual acidic potential of dew and frost. Theoretical calculations indicate that synergistic acidity from dew or frost in combination with dry deposition may result in very strong localized acidities.