Fresh Residues Research Articles

The collembolan Heteromurus nitidus grazes the wheat fungal pathogen Zymoseptoria tritici on infected tissues: opportunities and limitations for bioregulation.

Septoria tritici blotch (STB), caused by the fungus Zymoseptoria tritici, is a foliar disease affecting wheat crops against which conventional control methods are not totally effective. During inter-epidemic periods the fungus survives in wheat residues left on the ground. In this study, we tested the potential of the collembolan Heteromurus nitidus - a springtail species present in field soils and known to interact with different fungal species - as a potential bioregulation agent of Z. tritici on wheat residues through a choice and consumption experiment. Springtails preferred inoculated fresh residues but did not have a preference between inoculated and uninoculated old residues. Springtails grazed on Z. tritici fruiting bodies and reduced pycnidiospore numbers by ten-fold compared to control inoculated fresh residues. Attraction toward fresh inoculated residues and pycnidiospore reduction support the hypothesis that Z. tritici is a food source for springtails. Heteromurus nitidus showed no preference between inoculated and uninoculated 18-month-old residues, probably because they no longer produced ascospores. Attraction towards fresh residues and spore reduction support our hypothesis that H. nitidus may contribute to the bioregulation of Z. tritici. Perspectives for field application would be determined by the ability of H. nitidus and Z. tritici to interact at key epidemiological stages. The impact of H. nitidus on the quantity of pathogen primary inoculum over time should be estimated using residues of intermediate age. This would help to identify the optimal period for enhancing the effectiveness of springtails as consumers of Z. tritici. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Residual activity of insecticides against adult Systena frontalis (Coleoptera: Chrysomelidae) under semi-field conditions.

Systena frontalis (Fabricius) (Coleoptera: Chrysomelidae) is a serious insect pest in nursery production. Insecticides are an important control tactic for S. frontalis adults to reduce economic losses associated with its injury. Because densities and activity of S. frontalis adults are influenced by many biotic (e.g., adult emergence timing) and abiotic (e.g., fluctuating temperatures) factors in the nurseries, it is challenging to reliably determine the efficacy and residual activity of insecticides under field conditions. Thus, the objective was to determine the residual activity of common and alternative insecticides on adult S. frontalis under semi-field conditions. Field-collected S. frontalis adults were exposed to 0-, 7-, 14-, and 21-d-old, field-aged residue of 13 insecticides applied on panicled hydrangea (Hydrangea paniculata Siebold) shoots and maintained in the field. The fresh residues of tetraniliprole, cyclaniliprole, and sulfoxaflor + spinetoram were the most effective against S. frontalis adults, whereas only tetraniliprole and cyclaniliprole elicited evidence of efficacy when their residues were aged for a week. Fourteen- and 21-d-old residues of tetraniliprole were still effective on S. frontalis adults and reduced the injury. Based on the results, tetraniliprole, cyclaniliprole, and sulfoxaflor + spinetoram were effective for immediate management, cyclaniliprole can provide short-term efficacy, and tetraniliprole provides longer-term efficacy.

Lethal and behavioural toxicity of differently aged insecticide residues on European earwigs (Forficula auricularia) in the laboratory and in the field

Pesticide residues are an important topic in many environmental studies, but little is known about the effects of pesticide residues of different ages on beneficial arthropods. Therefore, in this study the activity of residues of three different ages of several commonly used insecticides on the behaviour and mortality of European earwigs was evaluated in the laboratory and the effect of the insecticides was verified in the field. All residues of the biorational SpinTor® (spinosad), Radiant SC (spinetoram), and the conventional Steward® (indoxacarb) showed significantly faster mortality progression compared to the control in the laboratory. All the Steward® residues caused a significant wave of erratic behaviour as the earwigs went through a deep and relatively long moribund stage and resurrected. We verified the effects of SpinTor® and Steward® on changes in earwig abundance and their behaviour in the orchard. Earwigs abundance was significantly lower 16 days after application of biorational SpinTor® and conventional Steward® which had a significantly more pronounced and longer lasting effect. The earwig population stabilised by day 53 after the insecticide applications. Field applications of insecticides had no effect on earwig behaviour and sex ratio. Our results show that older residues have a negative effect on European earwigs equal to that of fresh residues, although their degradation should occur. It is interesting to note that biorational insecticides may not be safer than chemical insecticides.

The effect of rice residue management on rice paddy Si, Fe, As, and methane biogeochemistry

Rice production results in residues of straw and husk, and the management of these residues has implications for the sustainability of the rice agroecosystem. Rice straw is typically incorporated into soil either as fresh residue or is burned prior to incorporation. Rice husk is not typically returned to rice fields. However, rice husk contains high levels of silicon, which has been shown to decrease rice accumulation of arsenic. In this work, we studied the resulting biogeochemical changes in rice paddy soils when paddies were amended with either straw or burned straw and either no husk, husk, or burned husk over two years. Using a full-factorial design, we observed that the higher lability of rice straw carbon controlled redox-sensitive processes despite the application of husk and straw at similar carbon rates. Amending paddies with straw, rather than burned straw, increased porewater Fe and As, plant As, and methane emissions regardless of husk amendment. Husk addition provided insignificant Si to the plant despite its high concentration of Si, suggesting limited short-term mobility of Si and that long-term additions of husk or higher rates may need to be studied.

Legume-based crop diversification reinforces soil health and carbon storage driven by microbial biomass and aggregates

Diversified cropping is a crucial management practice for increasing carbon (C) and nitrogen (N) sequestration in agroecosystems. However, knowledge gaps regarding the mechanisms by which diversified cropping affects C sequestration and soil quality remain unclear. Herein, a field experiment across six-year was performed to explore the effect of three contrasting cropping systems (i.e., winter wheat/summer maize, winter wheat/summer maize-early soybean, and nature fallow) on soil quality and C sequestration, as well as their main drivers at both 0–20 cm and 20–40 cm soil depths. Diversified cropping increased soil organic C (SOC) stock by 9% and the majority of the soil biochemical metrics in the topsoil despite a 40% reduction in the fertilizer application relative to wheat/maize. This was attributed to increased SOC content in large macroaggregates and enhanced microbial turnover due to diverse fresh residue inputs under diversified cropping. Alternatively, the soil organic C, microbial biomass C, C-acquisition enzyme activity, and N-acquisition enzyme activity in large macroaggregates (> 2 mm) were increased by 15%, 15%, 32%, and 16% in the topsoil under diversified cropping versus wheat/maize, respectively. Partial least squares path model displayed that increased C sequestration was mainly driven by microbial biomass C irrespective of the bulk- and aggregate scale. Furthermore, diversified cropping increased the soil quality index by 1- to 2-fold relative to maize/wheat since increased aggregate stability benefited soil structure and nutrient cycling regardless of soil depth. Overall, increased SOC stock is dominantly driven by microbial biomass C, and the improved soil quality is mainly impelled by soil organic C and aggregate stability in responding to diversified cropping were expected to create win-win scenarios for agroecosystems.

Coconut fatty acids exhibit strong repellency and week-long efficacy against several urban pest arthropods of the southwestern United States.

The southwestern United States is home to a variety of arthropods including Turkestan cockroaches, Blatta lateralis (Walker); hematophagous bugs, Tritoma rubida (Uhler); and Arizona bark scorpions, Centruroides sculpturatus (Ewing). These arthropods cause medical concern when they become established around homes and/or invade indoors. Traditionally, the management of these pests has relied primarily on the use of chemical insecticides; however, they offer poor prospects for control owing to their lack of efficacy as well as the effects of insecticides on humans and the environment. Botanical repellents are an option that has not been fully investigated for the management of these pests. Here, we investigated the behavioral responses of common urban pests of the southwestern USA to recently discovered coconut fatty acids (CFAs), to establish the potential use of these compounds as repellents. Fresh residues of CFA mixture (CFAm) and their constituents caprylic acid, capric acid, capric acid methyl ester, lauric acid, and lauric acid methyl ester, tested at a concentration of 1 mg cm-2 , strongly repelled all arthropods. The repellent activity of CFAm lasted for at least 7 days, and the addition of lavender oil, used as an odor-masking agent, did not decrease this effect. Concentrations of CFAm ten times lower (0.1 mg cm-2 ) still repelled Turkestan cockroaches, and concentrations 100 times lower (0.01 mg cm-2 ) repelled T. rubida and scorpions. CFAm and some of their constituents are efficacious, economical, and logistically feasible for inclusion in integrated pest management programs for these important urban pests of the southwestern USA. This article is protected by copyright. All rights reserved.

Repellency and Toxicity of Eight Plant Extracts against the Western Flower Thrips, Frankliniella occidentalis

We investigated the repellency and toxicity of eight plant extracts containing celangulin, cnidium lactone, matrine, nicotine, pyrethrins, rotenone, stemonine and veratrine against the western flower thrips (Frankliniella occidentalis Pergande; Thysanoptera: Thripidae). Flowers treated with 0.05% nicotine, pyrethrins, stemonine and rotenone harbored fewer western flower thrips in two- and multiple-choice repellency bioassays. When evaluated at concentrations varying from 0.005% to 0.1% in two-choice repellency bioassays, pyrethrins and rotenone were most repellent at 0.01% to 0.1%, and nicotine was most repellent at 0.025%. Mortality was 76% with 0.1% nicotine at 48 h, 78% with 0.5% stemonine at 72 h, and 100% with 0.1% pyrethrins and 0.5% rotenone at 48 h after contact with fresh (<1-d-old) residue. Effective residue age was 1 d for nicotine, pyrethrins and rotenone, and 5 d for stemonine in aged residual toxicity bioassays. Celangulin, cnidium lactone, matrine and veratrine did not provide sufficient repellency and toxicity. Stemonine had inconsistent results. Therefore, additional evaluation of its potential as a botanical insecticide will be needed. When sprayed onto whole plants, plant extracts containing nicotine, pyrethrins, rotenone and stemonine caused unacceptable damage to flowers, suggesting that the final formulation will need to be modified to improve crop safety.

Performance of Pyrethroid-Neonicotinoid Mixture Formulations Against Field-Collected Strains of the Tropical Bed Bug (Hemiptera: Cimicidae) on Different Substrates.

The residual performance of two pyrethroid-neonicotinoid mixture formulations: Temprid SC (10.5% beta-cyfluthrin and 21% imidacloprid) and Tandem (3.5% lambda-cyhalothrin and 11.6% thiamethoxam) on two substrates (glass and filter paper) against eight pyrethroid-resistant strains (BM-MY, BP-MY, CH-MY, GL-MY, KL-MY, SAJ-MY, TT-MY, and QLD-AU) of the tropical bed bug, Cimex hemipterus (F.) (Hemiptera: Cimicidae) collected from Malaysia, and Australia were evaluated. The aging effect of treatment residues on glass was also investigated. A susceptible C. lectularius L. strain (Monheim) was used for comparison. Temprid SC showed varying levels of performance against all C. hemipterus strains: TT-MY (PR50 = 6.5-fold, high performance), BM-MY, GL-MY, SAJ-MY, and QLD-AU (12.8-21.6-fold, moderate performance), BP-MY, and KL-MY (48.2-49-fold, poor performance), CH-MY (128.2-fold, very poor performance). On the other hand, Tandem displayed high performance against all C. hemipterus strains (1.8-8.3-fold). Tandem caused faster mortality than Temprid SC for all strains. Temprid SC and Tandem residues killed C. hemipterus significantly faster on glass than filter paper. Compared with fresh residues, the efficacy of Temprid SC residues significantly declined after one week of aging, while the effectiveness of Tandem residues declined after two weeks of aging. Further investigations using the topical assay method with a diagnostic dose of imidacloprid found two strains (CH-MY and GL-MY) resistant to imidacloprid. The six other strains (BM-MY, BP-MY, KL-MY, SAJ-MY, TT-MY, and QLD-AU) were susceptible.

Drying effects on Camu‐camu residue: An approach of mathematical modeling, thermodynamic properties, and color evaluation in order to obtain a natural food dye

The present study evaluated the drying of camu-camu pomace (reducing waste generation), and a mathematical model is proposed for drying at four different temperatures (60, 80, 100, and 120°C), and 1 m/s airflow. The thin-layer model that best fitted the experimental data was by Midilli, compared to ten other models. The evaluation method used the coefficient of determination (R2), RMSE (root mean square), and X2 (Chi-square), wherein the coefficient of determination remained >0.90. The activation energy calculated in the present study was 10.82 kJ mol−1, and effective diffusion coefficient D0 = 0.0012 (m2 s−1). Considering colorimetric parameters and the time of water mass loss, the temperature of 80°C is appropriate to produce a good powder. Thus, the drying of camu-camu pomace is an alternative to obtain a natural (red-purple) food dye. Novelty impact statement To our knowledge, the present study is a pioneer on the grounds that it presents the mathematical modeling data of the residue at high temperature, and also the obtention of camu-camu powder as natural dye. Considering the perishability of fresh residues, drying is one of the most feasible technological processes for the food industry, also to obtain natural dyes, highlighting to the natural powders. The modeling of drying curves provides an understanding as regards the physical and thermodynamic indices relevant to the heat and mass transfer process of the sample. So, this information is very important and might help to improve the performance of future analyses.

Towards a biorefinery processing waste from plantain agro-industry: Assessment of the production of dairy cattle feed through process simulation

The aim of this work was to design and analyse techno–economically and nutritionally the production of nutrient blocks and silage from waste of Dominico–Hartón plantain through process simulation in the framework of the design of a future biorefinery based on residues from plantain agro-industry. All systems were scaled to flows that would be realistically encountered in full–scale production systems, and several scenarios covering the production of supplementary feed blocks, fermented blocks, and silage for cattle feeding were considered. Plantain waste composition was determined experimentally. SuperPro Designer was used to simulate the process flowsheets. Process net present values were estimated using a project life of 15 years and an interest rate of 5.36%. Results suggested that fresh residues from plantain agro-industry are not recommended for dairy cattle consumption due to their high contents of moisture and neutral and acid detergent fibres, which provide few nutrients. Amending the residues with 19% maize forage resulted in a far better feed, with an estimated nutritional content of (on a dry basis): 28.34% neutral detergent fibre, 17.08% acid detergent fibre, 30.40% non–fibrous carbohydrates, and 34.52% moisture. The process flowsheets were modified by including a new step for moisture extraction as well. The feasible process for utilising plantain waste with the highest net present value (15.0 M$) was the production of supplementary feed blocks using screw press moisture extraction technology. This process can be incorporated as an alternative processing pathway into the design of a biorefinery using plantain waste as feedstock. • Plantain waste mixture is not suited for feeding dairy cattle due to high moisture. • This mixture may be adjusted by adding maize forage for feeding dairy cattle. • Nutrient blocks are an attractive alternative to valorise plantain residues. • Feasible process to produce supplementary feed blocks from waste was designed. • Process designed could be integrated into a biorefinery processing plantain waste.

Effect of Pretreatment and High Hydrostatic Pressure on Soluble Dietary Fiber in Lotus Root Residues

High hydrostatic pressure (HHP) can enhance the physicochemical properties of soluble dietary fiber (SDF) from fruit and vegetable residues including hydration properties, emulsibility, and rheological properties, while the pretreatment methods such as solid-water suspension status are ignored all along. Here, three groups of lotus root residue (LRR) for HHP treatment (400 MPa, 15 min) were prepared: the fresh lotus root residue (FLRR), FLRR mixed with water (FLRR + W), and dried FLRR suspended in water at the same solid/water level with FLRR + W (DLRR + W). As a control, non-HHP-treated FLRR was tested. Results showed that FLRR + W obtained the highest SDF yield and presented a honeycomb structure which was not observed in other LRR samples. In addition, properties of SDF extract from FLRR + W changed most significantly, including not only the enhancement of SDF yield, the improvement of hydration properties, and the reduction of molecular weight but also the increase of thermal and rheological stability. Principal component analysis (PCA) profile illustrated that the difference of LRR-water system contributed 27.6% to the SDF physicochemical changes, and SDF from DLRR + W distinguished it from the other samples with mannose, ribose, and glucuronic acid, indicating that the drying procedure also played a role in the HHP treatment focusing on the sugar constitution. Therefore, the solid-water suspension status is a noteworthy issue before HHP treatment aiming at SDF modification.

Applying cover crop residues as diverse mixtures increases initial microbial assimilation of crop residue-derived carbon.

Increasing the diversity of crops grown in arable soils delivers multiple ecological functions. Whether mixtures of residues from different crops grown in polyculture contribute to microbial assimilation of carbon (C) to a greater extent than would be expected from applying individual residues is currently unknown. In this study, we used 13C isotope labelled cover crop residues (buckwheat, clover, radish, and sunflower) to track microbial assimilation of plant residue‐derived C using phospholipid fatty acid (PLFA) analysis. We also quantified microbial assimilation of C derived from the soil organic matter (SOM) because fresh residue inputs also prime the decomposition of SOM. To consider the initial stages of residue decomposition, and preclude microbial turnover, we compared a quaternary mixture of residues with the average effect of their four components 1 day after incorporation. Our results show that the microbial biomass carbon (MBC) in the treatment receiving the mixed residue was significantly greater, by 132% (3.61 μg C g−1), than the mean plant residue‐derived MBC in treatments receiving the four individual components of the mixture. However, there was no evidence that the mixture resulted in any additional assimilation of C derived from native SOM than the average observed in individual residue treatments. We surmise that, during the initial stages of crop residue decomposition, a greater biodiversity of residues increases microbial assimilation to a greater extent than would be expected from applying individual residues either due to faster decomposition or greater carbon use efficiency (CUE). This might be facilitated by functional complementarity in the soil microbiota, permitted by a greater diversity of substrates, reducing competition for any single substrate. Therefore, growing and incorporating crop polycultures (e.g., cover crop mixtures) could be an effective method to increase microbial C assimilation in the early stages of cover crop decomposition.Highlights The effect of mixing crop residues on assimilation of C by soil microbial biomass was investigated.The study is important due to recent interest in diverse cover crop mixtures for arable systems.Mixing crop residues enhanced the assimilation of plant residue‐derived C into microbial biomass.Growing and incorporating cover crop polycultures may enhance C storage in arable soils.

Amendment of crop residue in different forms shifted micro-pore system structure and potential functionality of macroaggregates while changed their mass proportion and carbon storage of paddy topsoil

Soil organic carbon (SOC) sequestration in croplands was well known through physical protection of particulae organic carbon (POC) in macroaggregates, particularly with crop residue amendment. How different forms of crop residue could affect development of macroaggregates and their micro-pore system remained unclear. In a field experiment, a rice paddy was amended respectively with fresh (CS), manured (CM) and pyrolyzed (CB) maize residue at 10 t ha−1 in carbon equivalent, in comparison to no residue amendment (CK). In 3 years following amendment, undisturbed topsoil (0–15 cm) cores were collected under the treatments respectively. Following size fractionation of water-stable aggregates and SOC pool analysis, macroaggregate (MAC) samples were characterized with SR-µCT tomography. Compared to CK, bulk SOC storage increased by 13.9 % and 31.3 %, POC storage by 32.6 % and 63.3 % while MAC mass proportion by 7.4% and 24.5%, under CM and CB, respectively. Coincidently, total micro-porosity of MAC was increased by ca 30 % but porosity ratio of connected pores to isolated pores increased almost 1-fold though fractal dimension (FD) increased slightly, both under CM and CB. However, indices of pore throats were seen higher under CB than other treatments though micro-pore networking promoted under both CM and CB. In addition, micro-porosity and pore structure as well as POC were all observed similar between fresh residue and no residue treatments. Thus, crop residue amendment in different forms shifted micro-pore structure and potential functionality of MAC while changed their mass proportion and carbon storage of the paddy topsoil. Overall, crop residue recycled as biochar to paddy could ensure SOC sequestration through enhanced physical protection of POC in MAC, which could further potentially contribute to soil function improvement. How the short-term changes in macroaggregation and the pore system could contribute to the soil fertility and functioning deserve further studies.

Composting of Olive Mill Pomace, Agro-Industrial Sewage Sludge and Other Residues: Process Monitoring and Agronomic Use of the Resulting Composts.

The viability of co-composting of olive mill pomace added to sewage sludge with other organic residues was evaluated and the agronomic use of the final composts was investigated. Two composting piles at different carbon-nitrogen ratios were performed, in which olive mill pomace (OMP), sewage sludge from vegetable processing (SS), fresh residues from artichoke processing residues (AR), and wheat straw (WS) were used. The two composting piles were placed inside a specially built greenhouse and a turning machine pulled by a tractor was used for turning and shredding the organic matrix (every 6 days) during the process. The humidity and temperature of organic matrices have been monitored and controlled during the entire composting process, which lasted 90 days. The process was also monitored to evaluate the microbiological safety of the final compost. The humidity of both piles was always kept just above 50% until the end of the thermophilic phase and the maximum temperature was about 50 °C during the thermophilic phase. The carbon-nitrogen ratio decreased from 21.4 and 28.2, respectively (initial value at day 1 in Pile A and B), to values ranging from 12.9 to 15.1, both composts that originated from the two different piles were microbiologically safe. During a two-year period, the effects of different types of compost on the main qualitative parameters of processing tomato and durum wheat was evaluated. Five fertilization treatments were evaluated for tomato and durum wheat crops: unfertilized control (TR1); compost A (TR2); compost B (TR3); ½ mineral and ½ compost A (TR4); and mineral fertilizer commonly used for the two crops (TR5). Concerning the processing tomato yield, TR5 and TR4 showed the best results (2.73 and 2.51 kg, respectively). The same trend was observed considering the marketable yield per plant. The only difference was related to the treatments that included the compost (2.32, 1.77, and 1.73 kg/plant for TR4, TR3, and TR2, respectively). As regards the qualitative parameters of tomato, the highest average weight of the fruits was found in the TR5, TR4, and TR3 treatments (respectively, 73.67 g, 70.34 g, and 68.10 g). For durum wheat, only the protein component was differentiated between treatments. Furthermore, wheat grain yield parameters generally increased by combined application of mineral fertilizer and compost.

Chemical and Phytocoenological Characteristics of Two Different Slovak Peatlands.

This paper presents the results of pedological and phytocoenological research focused on the detailed research of chemical parameters (pH, organic carbon, and nutrients), risk elements (As-metalloid, Cd, Co, Cr, Cu, Ni, Pb, and Zn), and species composition of the vegetation of two different peatlands on the territory of Slovakia—Belianske Lúky (a fen) and Rudné (a bog). Sampling points were selected to characterize the profile of the organosol within the peatland, the soil profile between the peatland and the agricultural land, and the soil profile of the outlying agricultural land, which is used as permanent grassland. Based on phytocoenological records, a semi-quantitative analysis of taxa in accordance with the Braun–Blanquet scale was performed. The study revealed that the thickness of the peat horizon of the fen in comparison with the bog is very low. In terms of the quality of organic matter, the monitored peatlands are dominated by fresh plant residues such as cellulose and lignin. Differences between individual types of peatlands were also found in the soil reaction and the supply of nitrogen to the organic matter of peat. The values of the soil exchange reaction were neutral on the fen, as well as slightly alkaline but extremely low on the bog. A significantly higher nitrogen supply was found in the organic matter of the fen in contrast to the bog. At the same time, extremely low content of accessible P and an above-limit content of As in the surface horizons were also found on the fen. From the phytocoenological point of view, 22 plant species were identified on the fen, while only five species were identified on the bog, which also affected the higher diversity (H’) and equitability (e). The results of the statistical testing confirmed the diversity of the studied peatlands and the different impact of environmental variables on plant diversity.

Exploring Temperature-Related Effects in Catch Crop Net N Mineralization Outside of First-Order Kinetics

Catch crops are an effective method for reducing nitrogen (N) leaching in agriculture, but the mineralization of incorporated catch crop residue N is difficult to predict and model. We conducted a five-month incubation experiment using fresh residue from three catch crops (hairy vetch, fodder radish and ryegrass) with three temperature treatments (2 °C, 15 °C and 2–15 °C variable temperature) and two termination methods (glyphosate and untreated). Mineral N (ammonium and nitrate) in soil was quantified at 0, 1, 2, 4, 8 and 20 weeks of incubation. Ammonium accumulation from residue decomposition showed a lag at low and variable temperature, but subsequent nitrification of the ammonium did not. Mineral N accumulation over time changed from exponential to sigmoidal mode at low and variable temperature. Incubation temperature significantly affected mineralization rates in a first-order kinetics (FOK) model, while plant type and termination method did not. Plant type alone had a significant effect on the final mineralized fraction of added catch crop N. FOK models modified to accommodate an initial lag were fitted to the incubation results and produced better goodness-of-fit statistics than simple FOK. We suggest that initial lags in residue decomposition should be investigated for the benefit of mineralization predictions in cropping models.

Effects of spirotetramat insecticide on life history traits and population growth of Encarsia formosa (Hymenoptera: Aphelinidae)

ABSTRACT Sublethal effects of a spirotetramat insecticide on life history traits and population growth of two local Serbian populations (Bujanovac and Negotin) and one commercial Dutch population (the Dutch strain) of Encarsia formosa Gahan (Hymen.: Aphelinidae) were evaluated in laboratory bioassays. Median lethal concentrations of spirotetramat estimated in the acute toxicity bioassay with adults (250 mg/l for Bujanovac and Negotin populations, and 225 mg/l for the Dutch population), significantly reduced the longevity of adult wasps exposed for 48 h to fresh residues by 1.6–2.8 days. Total parasitism of exposed adults, adult emergence in the F1 generation, and the instantaneous rate of increase of surviving wasp populations were significantly reduced (<30%). When applied to pupae within parasitised hosts (at LC50s estimated in the acute toxicity bioassay with pupae; 700 mg/l for Bujanovac and 600 mg/l for the Negotin and Dutch populations), the spirotetramat significantly extended the development of juveniles (by 1–1.4 days), and significantly reduced longevity (by 0.7 days) and the instantaneous rate of increase for the Bujanovac wasps, by 6.1%. According to the estimated acute toxity for both adults and pupae of E. formosa and taking into account the reduction of reproductive and demographic parameters (<30% in bioassays with adults and <10% in bioassays with pupae), spirotetramat can be classified as compatible with E. formasa in integrated whitefly management.

Assimilation of Aboveground Litter Carbon Versus Soil Carbon by Collembola and Lumbricidae in Spruce Forest: A Litter Replacement Experiment

In a small-scale field experiment, we estimated the contribution of aboveground litter to the energy budget of different collembolan and earthworm species. In a 50-year-old spruce plantation, the natural spruce litter was replaced by an equivalent amount of maize litter. The natural difference in the isotopic composition of carbon (C) between the spruce and maize allowed us to estimate the proportions of different carbon sources in the tissues of soil animals. The dependence on litter-derived C was least pronounced in Collembola having low δ15N values, indicating the feeding on non-vascular plants. In contrast, collembolans having high δ15N values belonged to the food chains based on fresh plant residuals. These results suggest that different species of litter-dwelling collembolans may regulate substantially different energy channels. Some species of endogeic earthworms (Aporrectodea rosea and A. caliginosa) utilize aboveground plant residues, though soil organic matter and other belowground sources of carbon prevail in the energy budget of their populations.

Chemical composition of Bakken crude oil burn residue: Environmental relevance following train derailment fires

Shipments of Bakken crude oil by rail have increased in concert with the production of unconventional crude oil in the Williston Basin over the past 10 years, during which time multiple fiery train derailments resulted in tragic loss of life and/or environmental impacts. In this study the compositions of Bakken oil burn residues from a derailment fire(s) are compared to fresh and laboratory-evaporated Bakken crude oil. The absolute and hopane-normalized concentrations of n-alkanes, unsubstituted and substituted PAHs, and petroleum biomarkers and their percent depletions and enrichments (relative to hopane) are reported. Bakken oil burn residues lost 67–78% of their total chromatographable mass (C5 to C44) and exhibit chemical trends distinct from naturally-evaporated oil, including (1) the shape of their UCM profiles, (2) depletion of n-alkanes up to (at least) n-C30, (3) enrichment of priority pollutant (pyrogenic) PAHs, specifically favoring PAH isomers containing three or more linear aromatic rings (anthracene or benz[a]anthracene) or 5-member rings (fluoranthene or indeno[1,2,3-c,d]pyrene), and (4) depletion of some lower boiling petroleum biomarkers (C23-C25 tricyclic terpanes). Despite relative enrichment of most priority pollutant PAHs the absolute concentrations of both total PAH (TPAH50) and priority pollutant PAH (PPAH16) in the burn residues were depleted 69–78% and 41–48%, respectively, compared to fresh Bakken oil. These results demonstrate the changes and range of compositions among fresh, evaporated, and variably-combusted residues of Bakken crude oil, the latter of which are important in assessing the potential effect(s) of burn residues on the environment proximal to train derailment fires.

Using 3D digital microscopy and SEM-EDX for in-situ residue analysis: A multi-analytical contextual approach on experimental stone tools

Residue analysis is a sub-discipline in archaeology that uses a variety of techniques which can be useful for determining the function of prehistoric stone tools. Past experimental studies have revealed the non-diagnostic nature of residues under reflected light microscopy and the challenges of identifying them as plant or animal and assigning them to a specific origin (i.e. use-related vs incidental). Recently, new contextual approaches and analytical techniques have addressed these limitations. Prior studies have suggested that use-related and incidental residues can be identified on stone tool surfaces based on differences in distribution patterns. Location, residue frequency, and associations with other residues are often the main criteria used in these studies to distinguish use-related from incidental residues, while other contextual information such as directionality, aspects of crushing and smearing, or dispersion from the working edge are often ignored. Moreover, the integration of chemical information provided by other analytical techniques into these contextual approaches that address residue mapping has received little attention. In this study, we address these issues and combine contextual information recorded through 3D digital microscopy with elemental compositions obtained through SEM-EDX to better identify different animal and plant residues on experimental stone tools. Based on an experimental sample tested under outdoor field conditions, we show how identification issues in fresh undamaged residues are not only restricted to the ambiguity between different use-related remains, but also the ambiguity between the latter and incidental residues. We demonstrate the versatility of 3D DM in recording in-situ contextual information of fresh residues (distribution patterns, invasiveness, disposition of specific tissues indicating tool-use direction, and aspects of crushing and smearing) and how supporting this information with the elemental composition obtained through SEM-EDX and element maps can help to improve identification of ambiguous residues, both use-related and incidental. Although more experiments are needed, the multi-analytical contextual approach tested here provides an example of in-situ characterization of fresh undamaged residues in experimental tools that can be conducted before performing post-depositional experiments or using other analytical techniques and extraction protocols.