Effect of distribution and concentration of topically applied neonicotinoid insecticides in buffalograss,Buchloe dactyloides,leaf tissues on the differential mortality of Blissus occiduus under field conditions

BACKGROUND: Neonicotinoid insecticides are generally efficacious against many turfgrass pests, including several important phloem‐feeding insects. However, inconsistencies in control of western chinch bugs, Blissus occiduus, have been documented in field efficacy studies. This research investigated the efficacy of three neonicotinoid insecticides (clothianidin, imidacloprid and thiamethoxam) against B. occiduus in buffalograss under field conditions and detected statistically significant differences in B. occiduus numbers among treatments. A subsequent study documented the relative quantity and degradation rate of these insecticides in buffalograss systemic leaf tissues, using HPLC. RESULTS: Neonicotinoid insecticides initially provided significant reductions in B. occiduus numbers, but mortality diminished over the course of the field studies. Furthermore, while all three neonicotinoids were present in the assayed buffalograss leaf tissues, imidacloprid concentrations were significantly higher than those of clothianidin and thiamethoxam. Over the course of the 28 day study, thiamethoxam concentrations declined 700‐fold, whereas imidacloprid and clothianidin declined only 70‐fold and 60‐fold respectively. CONCLUSIONS: Field studies continued to verify inconsistencies in B. occiduus control with neonicotinoid insecticides. This is the first study to document the relative concentrations of topically applied neonicotinoid insecticides in buffalograss systemic leaf tissues. Copyright © 2012 Society of Chemical Industry     

Bound amino acids in humic acids from arable cropping systems

We investigated the varying concentrations of bound amino acids in humic acids (HA) extracted from soils under both crop rotation and continuous cropping of rye. The experiment was created in 1957. Since then, winter rye had been grown continuously and also the sequence of the 7 yr rotation had been started: potato, spring barley, alfalfa, alfalfa, oil seed rape, winter rye, and winter rye. Soils were fertilized with NPK and manure. Continuous cropping of rye increased total acidity of soils and the contents of carboxylic and phenolic groups in HA. The total amounts of the bound amino acids in HA from soils under crop rotation were higher than from continuous cropping of rye. Fertilization with NPK increased the contents of bound amino acids more than manure. Neutral amino acids dominated in all samples of HA, and basic amino acids had the lowest concentrations. In both types of cultivation, glutamic acids, glycine, alanine, valine, and lysine dominated. The proline contents in HA from continuous rye cropping were higher than in HA from soils under crop rotation. The concentrations of β‐alanine and lysine were higher in HA from crop rotation indicating a higher microbial biomass since these compounds are typical constituents of bacteria cell walls.     

Effects of Temperature,Sonication Time,and Power Settings on Size Distribution and Extractability of Total Wheat Flour Proteins as Determined by Size‐Exclusion High‐Performance Liquid Chromatography

The size‐exclusion (SE) HPLC profile of total protein extract obtained by sonication of flour samples at ambient temperature showed marked instability on reinjection. Instability was related to the presence of flour proteases that were inactivated by thermal treatment of flour samples at 60°C. Extraction of flour protein by sonication was a function of ultrasonic energy (sonication time × power product) delivered to flour sample. As protein solubility increased, the proportions of the earliest eluted SE‐HPLC fractions (F1 and F2) increased. Oversonication of proteins evidenced by a decrease in F1 amount at the benefit of F2 occurred below the sonication energy level needed for total protein extraction. Ultrasonic energy level was adjusted to allow total protein extraction while limiting oversonication. The sonication procedure was applied on 27 flour samples of contrasting dough strength to extract total proteins. Absolute amount of protein extractable by sonication, determined from SE‐HPLC area, was strongly correlated with flour protein content. Very significant and equivalent relationships were found between alveographic W index and absolute amount of either unextractable protein extract or F1 of SE‐HPLC profile from total protein extract.     

A comparative analysis of element composition of roots and leaves of barley seedlings grown in the presence of toxic cadmium,molybdenum, nickel,and zinc concentrations 1

Barley seedlings were grown in hydroponic culture in the presence of toxic concentrations of cadmium (Cd), molybdenum (Mo), nickel (Ni), and zinc (Zn) and analyzed for element composition [boron (B), calcium (Ca), Cd, iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), phosphorus (P), and Zn]. In a first survey, heavy metal concentrations were selected which resulted in a similar inhibition of root growth. Toxic concentrations of Cd, Mo, Ni, and Zn revealed both similar and distinct effects on specific leaf and root element contents. Examples for such responses were decreasing contents in root Mn and Mg at elevated levels of all heavy metals, including Mo, in the medium. In contrast, changes in root contents of B were specific for the applied type of heavy metal stress. The heavy metal dependent changes in B, Ca, Mg, and Mn contents were studied in more detail. In some cases, severe heavy metal toxicity caused excessive accumulation or depletion of nutrient elements that may be deleterious to the plants in addition to other primary damages caused by the heavy metal ions.     

A new large‐scale and cost‐effective restoration method for cold‐water coral gardens

1. Gorgonians dwelling on the Mediterranean continental shelf are among the most frequent fishing bycatch taxa. These species display several traits, such as long lifespans and slow growth, which make them very vulnerable to the impacts caused by fishing activities with far‐reaching and long‐lasting effects.
2. Hence, restoration and mitigation actions are crucial to enhance and speed up the natural recovery of damaged cold‐water coral gardens. Given the growing concern to develop effective and affordable restoration actions, the present study aims to propose and technically validate a new large‐scale and cost‐effective restoration method.
3. This technique, named ‘badminton method', consists of attaching bycatch Eunicella cavolini colonies to cobble supports and returning them to the continental shelf by gently throwing the gorgonian transplants directly from a boat.
4. Two consecutive field experiments were conducted in order to find the best cobble type support and gorgonian size to be used: first, to evaluate the landing efficiency of gorgonian transplants at different depths (from 5 to 30 m) and second, to evaluate their capability to maintain a correct position over time.
5. Natural cobbles with large gorgonians attached were the best option. Field results and modelling approaches suggest that the transplants would correctly land on the continental shelf seabed in a predicted area of around 60 m². Moreover, they would successfully maintain an upright position ensuring gorgonian survival over time.
6. The success of this method highlights the feasibility of large‐scale and low‐cost restoration actions with promising results for the conservation and recovery of cold‐water coral gardens.

     

Laboratory and on‐farm evaluation of low‐cost salt mixtures for use during salinity acclimation and the nursery phase of Pacific white shrimp (Litopenaeus vannamei)

The current study evaluates the efficacy of a low‐cost salt mixture (LCSM) to replace expensive reconstituted sea salt (RSS) in the salinity acclimation and nursery phase of Pacific white shrimp under laboratory and farm conditions. LCSM was formulated to yield sodium, potassium, calcium and magnesium concentrations closely comparable to that of diluted seawater. Laboratory‐based nursery trials were conducted at 2, 6 and 15 g/L salinities, incrementally replacing RSS with LCSM (25%, 50%, 75% and 100%) at four replicates per treatment. Thirty postlarvae were reared for 7 days in 24‐L aquaria during the 2 and 6 g/L trials, while the nursery trial for 15 g/L salinity was conducted for 21 days with 400 postlarvae stocked in 150‐L tanks. On‐farm evaluation of LCSM was carried out in two tank‐based systems installed on levees adjacent to shrimp production ponds. RSS was incrementally replaced with LCSM (0%, 50%, 75% and 100%) and 100 postlarvae stocked into each 800‐L tank. Salinity acclimation was done from 30 g/L to 6 or 1.5 g/L within 2–3 days by pumping water from adjacent shrimp production ponds. Following salinity acclimation, the S4 system maintained flow‐through at 1.5 g/L, while N10 system was maintained static at 6 g/L salinity. At the conclusion, no significant differences were observed for either survival or growth of shrimp postlarvae between RSS and LCSM treatments at all salinities examined. Results reflect the potential use of LCSM to replace RSS, which could be an excellent solution to bring down the cost of production in inland shrimp aquaculture.