Impact of landscape composition on honey bee pollen contamination by pesticides: a multi-residue analysis

The honey bee is the most common and important managed pollinator of crops. In recent years, honey bee colonies faced high mortality for multiple causes, including land-use change and the use of plant protection products (hereafter pesticides). This work aimed to explore how contamination by pesticides of pollen collected by honey bees was modulated by landscape composition and seasonality. We placed two honey bee colonies in 13 locations in Northern Italy in contrasting landscapes, from which we collected pollen samples monthly during the whole flowering season in 2019 and 2020. We searched for almost 400 compounds, including fungicides, herbicides, insecticides, and acaricides. We then calculated for each pollen sample the Pollen Hazard Quotient (PHQ), an index that provides a measure of multi-residue toxicity of contaminated pollen. Almost all pollen samples were contaminated by at least one compound. We detected 97 compounds, mainly fungicides, but insecticides and acaricides showed the highest toxicity. Fifteen % of the pollen samples had medium-high or high levels of PHQ, which could pose serious threats to honey bees. Fungicides showed a nearly constant PHQ throughout the season, while herbicides and insecticides and acaricides showed higher PHQ values in spring and early summer. Also, PHQ increased with increasing cover of agricultural and urban areas from April to July, while it was low and independent of landscape composition at the end of the season. The cover of perennial crops, i.e., fruit trees and vineyards, but not of annual crops, increased PHQ of pollen samples. Our work highlighted that the potential toxicity of pollen collected by honey bees was modulated by complex interactions among pesticide category, seasonality, and landscape composition. Due to the large number of compounds detected, our study should be complemented with additional experimental research on the potential interactive effects of multiple compounds on honey bee healt

Biodiversitätsmonitoring im Südtiroler Kräuteranbau = Biodiversity surveys in medicinal and aromatic plant fields in South Tyrol

Medicinal and aromatic plants in mountain regions such as South Tyrol are cultivated on small-scale farms, which are characterized by a high diversity of cultivated crop species grown on a relatively small area. This small-scale cultivation of medicinal and aromatic plants suggests that MAP fields are of high ecological value. However, research on this topic is generally lacking. In this study flower-visiting arthropods were recorded with pan traps in three herb fields during three survey events conducted in 2021. Our results indicate that medicinal and aromatic plant fields are valuable habitats for several taxa. In total 12.570 individuals were collected. Wild bees were particularly species-rich, accounting for 10 % of the regional wild bee species pool. Next to beneficial arthropods, potential pests, such as aphids were also highly abundant. However, natural enemies possibly counteracting pests were also numerous. Overall, we conclude that medicinal and aromatic plant cultivation may act as resource-rich oases for several arthropod groups, thereby promoting biodiversity also on a broader scale.Der Anbau von Arznei- und Gewürzpflanzen zeichnet sich in der Regel durch vielfältige Anbaukulturen auf relativ kleinen Flächen aus. Dies gilt insbesondere für Südtirol, wo diese Kulturen hauptsächlich von kleinen Betrieben im Berggebiet angebaut werden. Dieser kleinflächige Anbau von Arznei- und Gewürzpflanzen lässt vermuten, dass die Betriebe einen hohen ökologischen Wert haben. Es gibt wenige Studien zur Erfassung der Biodiversität im Anbau von Arznei- und Gewürzpflanzen. Daher wurden in dieser Arbeit Kräuteranbau-Betriebe als Lebensraum für blütenbesuchende Arthropoden untersucht. An drei Untersuchungsstandorten wurden im Jahr 2021 jeweils an drei Terminen Farbschalen zur Sammlung von Arthropoden verwendet. Kräuteranbau-Betriebe stellten sich als ein wertvoller Lebensraum für verschiedene Arthropoden heraus. Insgesamt wurden 12.570 Individuen mit den Farbschalen gesammelt. Insbesondere Wildbienen waren mit 10 % des regionalen Artenpools sehr artenreich. Auch potenzielle Schädlinge, wie zum Beispiel Blattläuse, waren sehr häufig anzutreffen, wobei natürliche Feinde, wie zum Beispiel Parasitoide, ebenfalls zahlreich vertreten waren. Insgesamt können Kräuteranbaubetriebe als strukturreiche Oasen für Arthropoden fungieren und sich somit auf einer breiteren Skala positiv auf die Biodiversität auswirken

Review on imidacloprid diffusion route and a case study: from apple orchard to the honey bee colony matrices

Honey bees play a pivotal role in natural and rural ecosystems by providing human and animal food sources through pollination services. However, in cultivated areas, they can be exposed to the chemicals utilized for crop protection. Neonicotinoid insecticides can adversely affect honey bee colonies impairing their survival, immunity and biological activities at lethal and sublethal doses. For this reason, neonicotinoids, together with other stress factors, like pathogens (e.g. viruses and Varroa mites), climate change and food shortage, are considered one of the causes of worldwide colony losses. Nevertheless, the natural way of entry and diffusion of these pesticides in field colonies is not completely clear. Here, we wanted to fill this gap by studying the diffusion route of imidacloprid and its metabolites by analysing different matrices collected from honey bee colonies used for pollination of apple orchards, in the framework of applied Integrated Pest Management strategies. Pollen, honey bees, honey, royal jelly, bee wax and bee bread were sampled from 6 honey bee colonies placed in two different apple orchards before blooming, exposed to chemicals application and removed from the site after that. Samples were analysed using a liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) in order to detect imidacloprid, olefin imidacloprid and 5-hydroxy imidacloprid. The results demonstrate that the primary way of entrance of imidacloprid was the pollen transported by foragers, while the main accumulation matrices were bee bread, honey and wax. These findings allow us to hypothesize that the accumulation of this insecticide, especially in bee bread, the main larval food, could potentially impact negatively on honey bee wellbeing at the adult stage. Moreover, our data could implement the honey bee colony simulato

THE ROLE OF MINERAL NUTRITION ON YIELDS AND FRUIT QUALITY IN GRAPEVINE, PEAR AND APPLE

ABSTRACT Fertilization of temperate fruit trees, such as grapevine ( Vitis spp.), apple ( Malus domestica), and pear ( Pyrus communis) is an important tool to achive maximum yield and fruit quality. Fertilizers are provided when soil fertility does not allow trees to express their genetic potential, and time and rate of application should be scheduled to promote fruit quality. Grapevine berries, must and wine quality are affected principally by N, that regulate the synthesis of some important compounds, such as anthocyanins, which are responsible for coloring of the must and the wine. Fermenation of the must may stop in grapes with low concentration of N because N is requested in high amount by yeasts. An N excess may increase the pulp to peel ratio, diluting the concentration of anthocyanins and promoting the migration of anthocyanins from berries to the growing plant organs; a decrease of grape juice soluble solid concentration is also expected because of an increase in vegetative growth. Potassium is also important for wine quality contributing to adequate berry maturation, concentration of sugars, synthesis of phenols and the regulation of pH and acidity. In apple and pear, Ca and K are important for fruit quality and storage. Potassium is the most important component of fruit, however, any excess should be avoided and an adequate K:Ca balance should be achieved. Adequate concentration of Ca in the fruit prevents pre- and post-harvest fruit disorders and, at the same time, increases tolerance to pathogens. Although N promotes adequate growth soil N availability should be monitored to avoid excessive N uptake that may decrease fruit skin color and storability

Net primary productivity, allocation pattern and carbon use efficiency in an apple orchard assessed by integrating eddy covariance, biometric and continuous soil chamber measurements

Carbon use efficiency (CUE), the ratio of net primary production (NPP) over gross primary production (GPP), is a functional parameter that could possibly link the current increasingly accurate global GPP estimates with those of net ecosystem exchange, for which global predictors are still unavailable. Nevertheless, CUE estimates are actually available for only a few ecosystem types, while information regarding agro-ecosystems is scarce, in spite of the simplified spatial structure of these ecosystems that facilitates studies on allocation patterns and temporal growth dynamics. <br><br> We combined three largely deployed methods, eddy covariance, soil respiration and biometric measurements, to assess monthly values of CUE, NPP and allocation patterns in different plant organs in an apple orchard during a complete year (2010). We applied a measurement protocol optimized for quantifying monthly values of carbon fluxes in this ecosystem type, which allows for a cross check between estimates obtained from different methods. We also attributed NPP components to standing biomass increments, detritus cycle feeding and lateral exports. <br><br> We found that in the apple orchard, both net ecosystem production and gross primary production on a yearly basis, 380 ± 30 g C m⁻² and 1263 ± 189 g C m⁻² respectively, were of a magnitude comparable to those of natural forests growing in similar climate conditions. The largest differences with respect to forests are in the allocation pattern and in the fate of produced biomass. The carbon sequestered from the atmosphere was largely allocated to production of fruit: 49% of annual NPP was taken away from the ecosystem through apple production. Organic material (leaves, fine root litter, pruned wood and early fruit falls) contributing to the detritus cycle was 46% of the NPP. Only 5% was attributable to standing biomass increment, while this NPP component is generally the largest in forests. <br><br> The CUE, with an annual average of 0.71 ± 0.12, was higher than the previously suggested constant values of 0.47–0.50. Low nitrogen investment in fruit, the limited root apparatus, and the optimal growth temperature and nutritional condition observed at the site are suggested to be explanatory variables for the high CUE observed