Unravelling pest infestation and biological control in low-input orchards: the case of apple blossom weevil

Low-input farming is an alternative production system that provides a great opportunity to disentangle the natural mechanisms regulating crop pests, since neither pests nor their natural enemies are disrupted by pesticides. Here, we use a key apple pest in Europe, the apple blossom weevil (Anthonomus pomorum), as a model case to unravel the factors driving pest infestation and its biological control in a low-input context, namely the cider apple orchards of NW Spain. We applied a holistic approach based on the complete life cycle of the pest and combined large-scale observation (23 orchards) with small-scale experimental assessment. Weevil attack (0.4–37.4% of flowers) increased with the proportion on apple trees in the immediate orchard neighbourhood and with semi-natural woody habitat in the surrounding landscape and decreased with tree distance to orchard edge and apple bloom level. Thus, the prevalence of the pest depended on the availability of the various resources required for foraging, egg-lying and overwintering. Three types of natural enemies supplied complementary pest control by preying on weevils at different stages in their life cycle: seven parasitoid species attacked immature weevils (6.4–81.5%), while the additive effects of birds and crawling arthropods were evident in terms of the removal of adult weevils (31–44%). We conclude that the effective biological control of A. pomorum can be achieved in low-input systems to maintain the pest at non-harmful levels, through combined management of the pest, its habitat and its natural enemies.     

Evidence for natural resistance towards trifloxystrobin in <Emphasis Type="Italic">Fusarium graminearum</Emphasis>

A collection of 55 Fusarium graminearum (Gibberella zeae) strains isolated between 1969 and 2009 in Belgium, Canada, Germany, Italy, Luxembourg, or the USA belonging to the three known chemotypes (3-acetylated deoxynivalenol, 15-acetylated deoxynivalenol and nivalenol) were screened for their sensitivity towards the fungicide trifloxystrobin using a liquid culture assay. None of the isolates was completely inhibited by trifloxystrobin concentrations up to 3 mM. For comparison, prothioconazole completely inhibited fungal growth of a standard isolate at concentrations as low as 0.007 mM. The maximum level of inhibition, which could be obtained by trifloxystrobin, ranged from 14 to 65% among the strains tested and was not significantly affected by the country of origin or by the chemotype. The absence of significant differences in resistance levels between the countries of origin and chemotypes as well as the fact that strains isolated before the market introduction of strobilurins in 1996 also showed a high level of resistance is evidence that this is largely a case of natural resistance and not primarily related to strobilurin use in agriculture.     

Effect of grape seed and skin supplement on milk yield and composition of dairy ewes

In the present study, we investigated the effect of grape seed and skin supplement (GSSS), on lactating dairy ewes’ production. Ten dairy pregnant ewes from northern Tunisia were allocated to two groups: control diet (C) and supplemented with 20 % (w/w) GSSS. The experiment lasted for 8 weeks and took place after 2 months of lambing. During the experiment, daily milk yield and milk composition were determined. Supplementation of the diet with GSSS increased milk production (P?<?0.001), calcium (P?<?0.01), free iron (P?<?0.01) and urea content (P?<?0.001) but had no effect on milk fat nor protein. From these data, it is concluded that the inclusion of GSSS in sheep diets increased significantly ewes’ milk yield.     

Hypertrophic osteopathy associated with hepatocellular carcinoma in a dog

A 9-year-old spayed female dog diagnosed with hepatocellular carcinoma and hypertrophic osteopathy was negative for additional lesions on computed tomography of the thorax and abdomen. Resection of the affected liver lobe resulted in resolution of clinical signs. This is the first case of hypertrophic osteopathy secondary to hepatocellular carcinoma.     

Molecular diversity of Moraxella bovis isolated from Brazil, Argentina and Uruguay over a period of three decades

The molecular profile of 30 Moraxella bovis strains, recovered from outbreaks of infectious bovine keratoconjunctivitis in Argentina, Brazil and Uruguay between 1974 and 2001, was determined through randomly applied polymorphic DNA (RAPD) analysis. Molecular profiles of nine strains recovered after 1990 varied from those recovered before 1990. The profiles of 13 strains (48%) differed from those of three vaccinal strains extensively used since 1984 in Argentina and Uruguay. Eight Argentinean strains, one from Brazil and two from Uruguay had identical RAPD profiles. Strains belonging to different serogroups had identical RAPD profiles, demonstrating that this technique was not able to discriminate among strains with low cross-reactivity indices. RAPD may be helpful in the primary characterization of M. bovis strains, but it does not replace serological characterization.     

Porcine salivary analysis by 2-dimensional gel electrophoresis in 3 models of acute stress: A pilot study

The purpose of this research was to study changes in the salivary proteome of healthy pigs in stressful situations to identify any potential new salivary biomarker of stress. Three groups of animals were subjected to 3 stress models: snaring restraint followed by simulated sampling of vena cava blood; brief transport by road; and restriction of movement in a digestibility cage. Saliva was obtained from each animal before and 15 and 30 min after the induction of stress. The samples from the animals that showed the greatest increase in salivary cortisol concentration were pooled and run on 2-dimensional gels. Coomassie Brilliant Blue R-250 was used for spot detection and mass spectrometry for spot identification. Statistical analyses showed that 2 proteins had significant differences in expression before and after the induction of stress. These proteins were identified as odorant-binding protein and fragments of albumin. Further studies will be necessary to confirm the value of using these proteins as salivary biomarkers of stress in pigs.     

Biodegradation of carbofuran by <Emphasis Type="Italic">Pichia anomala</Emphasis> strain HQ-C-01 and its application for bioremediation of contaminated soils

A novel yeast named HQ-C-01 was isolated from activated sludge and identified as Pichia anomala based on the morphology and 18S rDNA sequence analysis. The HQ-C-01 strain degraded 95.2% of carbofuran when the insecticide was used as the only C source and added at 50 mg/L in a mineral salts medium within 48 h. The optimal concentration, temperature, and pH of medium for degradation of carbofuran were 50 mg/L, 30°C, and pH 7.5, respectively. Strain HQ-C-01 could also effectively degrade other carbamate insecticides including carbaryl, indoxacarb, and fenobucarb, and the degradation rates were 99%, 85%, and 67%, respectively. Gas chromatography–mass spectrometry analysis showed that the strain metabolized carbofuran to produce benzofuranol as the intermediate metabolite, which was further degraded. Degradation of carbofuran added at 50 mg/kg of soil was higher in yeast-inoculated soil than in the control. These results indicated that strain HQ-C-01 may potentially be used in bioremediation of carbofuran-contaminated soil.     

Biochar-induced changes in soil properties affected immobilization/mobilization of metals/metalloids in contaminated soils

Purpose

Remediation of metal contaminated soil with biochar is attracting extensive interest in recent years. Understanding the significance of variable biochar properties and soil types helps elucidating the meticulous roles of biochar in immobilizing/mobilizing metals/metalloids in contaminated soils.

Materials and methods

Six biochars were produced from widely available agricultural wastes (i.e., soybean stover, peanut shells and pine needles) at two pyrolysis temperatures of 300 and 700 °C, respectively. The Pb-, Cu-, and Sb-contaminated shooting range soils and Pb-, Zn-, and As-contaminated agricultural soils were amended with the produced biochars. The mobility of metals/metalloids was assessed by the standard batch leaching test, principal component analysis and speciation modeling.

Results and discussion

The changes in soil properties were correlated to feedstock types and pyrolysis temperatures of biochars based on the principal component analysis. Biochars produced at 300 °C were more efficient in decreasing Pb and Cu mobility (>93 %) in alkaline shooting range soil via surface complexation with carboxyl groups and Fe-/Al-minerals of biochars as well as metal-phosphates precipitation. By contrast, biochars produced at 700 °C outperformed their counterparts in decreasing Pb and Zn mobility (100 %) in acidic agricultural soil by metal-hydroxides precipitation due to biochar-induced pH increase. However, Sb and As mobility in both soils was unfavorably increased by biochar amendment, possibly due to the enhanced electrostatic repulsion and competition with phosphate.

Conclusions

It is noteworthy that the application of biochars is not equally effective in immobilizing metals or mobilizing metalloids in different soils. We should apply biochar to multi-metal contaminated soil with great caution and tailor biochar production for achieving desired outcome and avoiding adverse impact on soil ecosystem.

     

The potential of hyperspectral images and partial least square regression for predicting total carbon,total nitrogen and their isotope composition in forest litterfall samples

Purpose

The main objective of this study was to examine the potential of using hyperspectral image analysis for prediction of total carbon (TC), total nitrogen (TN) and their isotope composition (δ¹³C and δ¹⁵N) in forest leaf litterfall samples.

Materials and methods

Hyperspectral images were captured from ground litterfall samples of a natural forest in the spectral range of 400–1700 nm. A partial least-square regression model (PLSR) was used to correlate the relative reflectance spectra with TC, TN, δ¹³C and δ¹⁵N in the litterfall samples. The most important wavelengths were selected using β coefficient, and the final models were developed using the most important wavelengths. The models were, then, tested using an external validation set.

Results and discussion

The results showed that the data of TC and δ¹³C could not be fitted to the PLSR model, possibly due to small variations observed in the TC and δ¹³C data. The model, however, was fitted well to TN and δ¹⁵N. The cross-validation R² _cv of the models for TN and δ¹⁵N were 0.74 and 0.67 with the RMSE_cv of 0.53% and 1.07‰, respectively. The external validation R² _ex of the prediction was 0.64 and 0.67, and the RMSE_ex was 0.53% and 1.19 ‰, for TN and δ¹⁵N, respectively. The ratio of performance to deviation (RPD) of the predictions was 1.48 and 1.53, respectively, for TN and δ¹⁵N, showing that the models were reliable for the prediction of TN and δ¹⁵N in new forest leaf litterfall samples.

Conclusions

The PLSR model was not successful in predicting TC and δ¹³C in forest leaf litterfall samples using hyperspectral data. The predictions of TN and δ¹⁵N values in the external litterfall samples were reliable, and PLSR can be used for future prediction.

     

Establishment of a comprehensive indicator system for the assessment of biodiversity and ecosystem services

Context

Common indicators are needed to monitor biodiversity loss and the implications for the sustainable provision of ecosystem services (ES). A plethora of different sets of indicators may hinder the identification of major endpoints for large-scale assessments of biodiversity and ecosystem services (BES).

Objectives

We aim to describe the main challenges of indicators for BES assessment and provide suggestions for establishing a comprehensive indicator system.

Methods

An extensive literature review was conducted in this study. We review the main challenges of indicators for BES assessment and propose corresponding improvements from our perspectives of theory and practical applications.

Results

The main theoretical challenges of existing indicators include inconsistent definitions and classifications of ES, misunderstanding of linkages among biodiversity, ecosystem structure, functions and services, and practical problems relate to such issues as indicator representativeness, data availability, and uncertainty. Our suggested improvements include clarifying the main terms, concepts and classification of indicators, establishing a robust conceptual framework with clear interactions among different components and indicators, selecting indicators based on ecosystem properties, streaming existing data into one platform, and strengthening validation of proxies. The steps for constructing a comprehensive indicator system for BES assessment are summarized.

Conclusions

Clear definitions of key terms are indispensable to classify indicators and construct a conceptual framework. Improved understanding of the relations among indicators of biodiversity, ecosystem functions, and ES across multiple scales can guide the development of the indicator system. The integrated indicator system is an important tool for BES assessment to support decision making for sustainable development.