Physical and Chemical Characteristics of Bottom Soil Profiles in Ponds at Auburn, Alabama, USA and a Proposed System for Describing Pond Soil Horizons

Soil cores were taken from each of three, 2-, 23-, and 52-yr-old research ponds (650–1,010 m² area) at Auburn, Alabama. Many physical and chemical variables changed in intensity with increasing depth in cores. Compared to original compacted pond soil, sediment contained more moisture; had lower bulk density (<1.4 g/cm³); possessed higher percentages of silt and clay; had greater porosity, specific surface area, and cation exchange capacity; and contained greater concentrations of organic matter and nutrients. Sediment organic matter was highly decomposed as evidenced by low proportions (5–15%) of carbon and nitrogen associated with the light fraction (soil retained on a 53-μm sieve). Sediment depth at 100-cm water depth increased with pond age (11.7 cm, 28.3 cm, and 48.3 cm in 2-, 23-, and 52-yr-old ponds, respectively), but sediment composition did not change greatly over time. Successive layers in cores were as follows: 1) water near the soil-water interface with a high concentration of solids; 2) high moisture content sediment with dry bulk density <0.3 g/cm³; 3) lower moisture content sediment with bulk density between 0.3 and 0.5–0.7 g/cm³; 4) rapid transition of bulk density from 0.5–0.7 g/cm³ to 1.4 g/cm³; 5) original compacted soil with bulk density of 1.4–1.7 g/cm³. We propose that these five layers be referred to as F (flocculent layer), S (stirred or mixed sediment), M (mature, bulk, un-mixed sediment), T (transitional layer), and P (original, undisturbed pond bottom) horizons, respectively. Superficial, oxidized sediment is termed an S_o horizon, and the reduced part of the S horizon is termed an S_r horizon. The upper part of the T horizon is an MT horizon when it is similar to the M horizon, or a FT horizon when it resembles the P horizon. A system for delineating horizons in pond soil profiles will be valuable in future attempts to classify pond soils.     

在美国使用无纺布菌条防治光肩星天牛的前景

An invasive long-horned beetle,Anoplophora glabripennis,was first reported in the northeastern and midwestern United States and eastern Canada between 1996 and 2004 and has been given the common name Asian longhorned beetle (ALB). This beetle has also been found in several countries in Europe.ALB is difficult to control because larvae are found within the wood of living trees and the long-lived adults often occur high in tree canopies.This species is native to China and Korea and,because it has been a major tree killer in China,government agencies in the U.S.and Canada are working to eradicate ALB from North America.Our laboratory has been developing a microbial control approach targeting ALB adults,based on the Japanese product Biolisa Kamikiri which is used to control cerambycids in orchards.Entomopathogenic fungi are grown within non-woven fiber bands (= fungal bands) and placed around tree trunks and branches where ALB adults become inoculated when walking across bands. We have conducted bioassays with Beauveria brongniartii,Beauveria bassiana and Metarhizium anisopliae against ALB larvae and adults to identify effective isolates and now focus our efforts on M.anisopliae F52 (ARSEF 7711). Caged field trials conducted in China to compare fungal sprays with fungal bands (2000, 2001) demonstrated decreased ALB longevity and fitness for both application methods but longer activity of fungi in cages treated with fungal bands compared with sprays.Uncaged field trials (2001, 2002) yielded faster ALB adult mortality in fungal-treated plots and decreased fitness. Studies in New York City testing the longevity of activity of fungal bands in the field have documented that bands retain＞1×107 conidia·cm-2 (the threshold for activity of Biolisa Kamikiri) for over 3 months.In contrast, studies with unformulated conidia sprayed onto tree trunks in New York documented conidial survival of only a few days.Sublethal effects of exposure of adult female ALB to fungal bands have been investigated further in the laboratory.After either newly eclosed or reproductively active females are exposed to fungal bands,few viable larvae are produced before death of the females.When females are exposed to fungal bands and then caged with males,males become infected.     

Introduction of the entomopathogenic fungusEntomophaga maimaiga hum.,

The entomopathogenic fungusEntomophaga maimaiga was introduced into aL. dispar population situated in South Bulgaria for the first time in Europe. It was found that of all larvae collected in the five experimental plots, 6.3 % contained conidia and resting spores ofE. maimaiga, 14.2 % contained parasitoids and 2.3 % were infected with nucleopolyhedrovirus (NPV). The presence of the fungus in cadavers collected from each experimental plots and on five of the six collection dates was observed.     

Further spread of the gypsy moth fungal pathogen,Entomophaga maimaiga,to the west and north in Central Europe

Journal of Plant Diseases and Protection - The gypsy moth, Lymantria dispar, is one of the most important pests of deciduous trees in Europe, occurring in all environmental zones of Europe except...     

GC analysis of essential oils in the rumen fluid after incubation of Thuja orientalis twigs in the Rusitec system

Methods for the chemical analysis of toxic plant substances in the rumen of ruminants are of importance for the diagnosis of intoxications with poisonous plants. The present work establishes a method to estimate monoterpene components of the essential oil of thuja (Thuja orientalis, Cupressaceae) in these types of samples. Alpha-thujone, which is regarded as the toxic principle, is present at a concentration of 50-60% in the essential oil. The rumen simulation technique (Rusitec) was used to simulate natural digestion. Chopped twigs of thuja were subjected to rumen content in a closed container with an overflow device. The flow of saliva was simulated by the continuous addition of a buffer solution. Samples for analysis were taken from the overflow at 24 and 48 h. A further sample was taken from the remaining liquid fraction of the rumen content in the container at 48 h. The essential oils were extracted with hexane and concentrated. A quantitative determination was done by capillary gas chromatography. Together in the three fractions analysed this resulted in total mean recoveries of 6.8% for alpha-thujone, 5.3% for beta-thujone, 18.9% for fenchone and 27.8% for camphor. The observation that the thujones were recovered to a lesser extent than other oil components is evidence of their fast decomposition in the rumen medium. Under these circumstances the calculated detection limit is 100-200 g thuja twigs in cows with rumen volumes of 60-100 litres. The main essential oil degradation products found in the rumen fluid of all three fractions in the Rusitec system were discovered to be iso-3-thujanol, neo-3-thujanol, carvomenthol and carvomenthone.