The dynamics of introduction of alien scale insects (Hemiptera: Coccoidea) into Croatia

In recent years, several species of alien scale insects have arrived and spread rapidly through European and Mediterranean countries. One hundred and twenty‐nine species of alien scale insects have so far been recorded in Europe. This paper presents a list of alien scale insect species for Croatia, comprising 56 species from 8 different families. Four of them are new records for Croatia: Aonidiella taxus Leonardi, 1906, Ichnaspis longirostris (Signoret, 1882), Phoenicococcus marlatii (Cockerell, 1899) and Spilococcus mammillariae (Bouche, 1844). The majority of species recorded belong to the following families: Diaspididae (28 species), Coccidae (12 species), Pseudococcidae (10 species), Eriococcidae (two species). The scale insect families Dactylopidae, Margarodidae, Ortheziidae and Pheniococcidae comprised only one recorded alien species each. During the time frame covered in the review (from the beginning of the 20th century until 2015), the majority of alien scale insect species (23) were registered in the period from 2000 to 2015. Data on the origin of introduced alien scale insects shows that the majority of the species originate from Asia (22 species), followed by North America (6 species), Africa, Australia and Central America (5 species each) and South America (4 species), with 9 species being of unknown origin.     

Oxidant/antioxidant properties of Croatian native propolis

Native propolis was defined as propolis powder collected from the continental part of Croatia and prepared according to a patented process that preserves all the propolis natural nutritional and organoleptic qualities. Nine phenolic compounds (out of thirteen tested) in propolis sample were detected by high performance liquid chromatography (HPLC) analysis. Among them chrysin was the most abundant (2478.5 microg/g propolis). Contrary to moderate antioxidant activity of propolis examined in vitro (ferric reduction antioxidant power; FRAP-assay), propolis as a food supplement modulated antioxidant enzymes (AOE) and significantly decreased lipid peroxidation processes (LPO) in plasma, liver, lungs, and brain of mice. The effect was dose- and tissue-dependent. The lower dose (100 mg/kg bw) protected plasma from oxidation, whereas the higher dose (300 mg/kg bw) was pro-oxidative. Hyperoxia (long-term normobaric 100% oxygen) increased LPO in all three organs tested. The highest vulnerability to oxidative stress was observed in lungs where hyperoxia was not associated with augmentation of AOE. Propolis protected lungs from hyperoxia by increased catalase (CAT) activity. This is of special importance for lungs since lungs of adult animals are highly vulnerable to oxidative stress because of their inability to augment AOE activity. Because of its strong antioxidant and scavenging abilities, native propolis might be used as a strong plant-based antioxidant effective not only in physiological conditions but also in cases that require prolonged high concentration of oxygen.     

An outbreak of tick paralysis in free-ranging mouflon (Ovis ammon musimon)

During November 2006, two live and one dead mouflon (Ovis ammon musimon) were presented with a history of weakness, tremors, and paralysis. After a detailed gross and histologic examination and a bacteriologic, parasitologic, and rabies evaluation, a preliminary diagnosis of tick paralysis was established. A thorough field search revealed 13 affected mouflons found in the open hunting ground "Sveti Juraj" near the town of Senj (Croatia), along with an additional 35 mouflon carcasses. All 13 mouflons were placed in a quiet, semidark stable. All detectable ticks were removed manually, and the animals were topically treated with 250 ppm of Amitraz water emulsion (Taktic 12.5% EC, Intervet International, 5830 Boxmeer, Netherlands). The collected ticks were identified as Ixodes ricinus, Dermacentor marginatus, and Haemaphysalis punctata. In the following 24 hr, all treated animals recovered fully. This report describes a naturally occurring outbreak of tick paralysis in free-ranging mouflons from a karst habitat.     

Modeling the impact of global change on regional agricultural land use through an activity-based non-linear programming approach

Assessing the impact of climate change on agriculture is a new challenge for quantitative model-based policy analysis. The impact of climate change will vary strongly across regions depending on pre-existing climatic, agronomic, and political conditions. Most of the present modeling approaches, which aim to analyze the impact of global change on agriculture, deliver aggregated results both with regard to content and spatial resolution. To deliver results with a higher spatial resolution and to produce a more detailed picture of agricultural production, the county-based agro-economic model known as ACRE-Danube was developed. The German and Austrian part of the Upper Danube basin, a study area with great diversity in agricultural landscapes and climatic conditions, was chosen for study. For the analysis, two scenarios of climatic and socio-economic change were derived. The first and more economically and globally oriented scenario, termed “Full Liberalization,” included significant temperature increases. The second and more environmentally and regionally oriented “Full Protection” scenario included a moderate temperature increase. Both scenarios produce different results regarding agricultural income and land use. While the developments in the Full Protection scenario are small, the Full Liberalization scenario yields extreme regional changes in agricultural income, an increase in cereal production and extensive grassland farming.     

Testing the influence of sediment granulometry on heterotrophic respiration with a new laboratory flow-through system

Purpose

Increased sedimentation due to land use intensification is increasingly affecting carbon processing in streams and rivers around the globe. This study describes the design of a laboratory-scale flow-through incubation system as a tool for the rapid estimation of sediment respiration. The measurements were compared with those obtained using an in situ closed chamber respiration method. The influence of sediment size on respiration rates was also investigated.

Materials and methods

Measurements were conducted on a pre-alpine gravel-bed river sediment separated into the following grain size fractions: > 60 mm (14.3%), 60–5 mm (60.2%), 5–2 mm (13.7%), 2–0.063 mm (11.1%) and <0.063 mm (0.6%). Concurrently, in situ and laboratory measurements were carried out on a naturally heterogeneous sediment. In situ respiration was determined in closed chambers as O₂ consumption over time, while in the laboratory, respiration was determined using flow-through respiration chambers. Oxygen concentrations were measured using a fibre-optic oxygen meter positioned at the inflow and outflow from the chamber.

Results and discussion

The mean respiration rates within naturally mixed riverbed sediments were 1.27 ± 0.3 mg O₂ dm^?3 h^?1 (n = 4) and 0.77 ± 0.1 mg O₂ dm^?3 h^?1 (n = 3) for the flow-through chamber system and closed chamber system, respectively. Respiration rates were statistically significantly higher in the flow-through chamber system (t test, p < 0.05), indicating that closed chamber measurements underestimated the oxygen consumption within riverbed sediments. Sediment grain size was found to significantly affect respiration rates in both systems (ANOVA, p < 0.001) with the fine sediment fraction (particle size <0.063 mm) having the highest respiration rate (r_flow-through = 51 ± 23 mg O₂ dm^?3 h^?1). The smallest fractions (2–0.063 and <0.063 mm), which represent approximately 12% of total sediment volume, contributed 60% of total respiration.

Conclusions

The study demonstrated that flow-through respiration chambers more accurately estimate the respiration rate within riverbed sediments than in situ closed chambers, since the former experiment imitates the natural conditions where continuous interstitial flow occurs in the sediments. We also demonstrated that fine sediments (<5 mm) substantially contribute to heterotrophic respiration in the studied gravel-bed river.

     

Genetic diversity and origin of cultivated potatoes based on plastid microsatellite polymorphism

The origin of cultivated potatoes has remaining questions. In this study, 237 accessions of all cultivated species and 155 accessions of wild species closely related to cultivated potatoes, including their putative ancestors, were analyzed using 15 plastid microsatellites (SSRs) to investigate genetic diversity and their relationships with the wild species. We here used polymorphic plastid SSRs we developed from potato plastid genome sequences as well as already known plastid SSR markers. All 15 loci were polymorphic and identified a total of 127 haplotypes. Dramatic decreases in levels of genetic diversity were revealed in landraces in comparison with wild ancestor species. The plastid SSR results showed a decrease in haplotype number and diversity from Peru to both north and south. Phylogenetic analysis revealed two distinct groups. One of them, group A, contained the majority of accessions of cultivated species of the Solanum tuberosum Andigenum group including all accessions of cultivated diploid and triploid cytotypes of this group (S. chaucha, S. phureja, and S. stenotomum by a former taxonomic system) and most of tetraploid accessions of the S. tuberosum Andigenum group (S. tuberosum subsp. andigenum), and the majority of accessions of wild ancestors from the northern members of the S. brevicaule complex. Another group B comprised most of the wild species accessions and almost exclusively hybrid cultivated species which have introgressed plastid genomes from the other wild gene pools. Lack of clustering of traditional cultivated species (as used above) support a revised group classification of S. tuberosum.     

Temporal changes in the prevalence and shedding patterns of Giardia duodenalis cysts and Cryptosporidium spp. oocysts in a herd of dairy calves in Ontario

Giardia duodenalis and Cryptosporidium spp. infections, and the patterns of cyst and oocyst shedding, were observed in a herd of dairy calves in Ontario over a period of 3 mo. Cysts and oocysts were detected and enumerated in fecal samples using immunofluorescence microscopy; Giardia and Cryptosporidium DNA was detected using the polymerase chain reaction. The prevalence of G. duodenalis increased during the course of the study, reaching a peak of 93.1% when calves were 43 to 54 d old, and then decreased. Conversely, Cryptosporidium spp. prevalence was highest (75.9%) when calves were 11 to 22 d old, and subsequently decreased. The numbers of cysts and oocysts shed per gram of feces were positively correlated over time with the respective prevalence rates. Along with genotyping data, temporal changes in prevalence and shedding patterns should be considered when testing dairy calves for the presence and concentrations of cysts and oocysts, and when considering the potential for zoonotic transmission.     

Nutrients,Antioxidant Capacity and Safety of Hot Water Extract from Sugar Maple (<Emphasis Type="Italic">Acer saccharum</Emphasis> M.) and Red Maple (<Emphasis Type="Italic">Acer rubrum</Emphasis> L.) Bark

Sugar maple (Acer saccharum M.) and red maple (Acer rubrum L.) barks were treated with hot water to extract nutrients in order to explore, for the first time, its potential as safe dietary antioxidants. The organic and inorganic nutrients of these extracts, as well as their safety on human PLB-985 cells differentiated into neutrophils-like cells, were determined. Proximate analysis showed that both bark extracts were low in moisture and fat. Sugar maple bark extract (SM-BX) showed crude protein and ash content higher than those found in red maple bark extract (RM-BX). In addition, SM-BX had total sugars higher than those evaluated in RM-BX, while complex sugars (oligo- and/or poly-saccharides) were similarly abundant in both bark extracts. Furthermore, SM-BX demonstrated a wide array of vital minerals (K, Ca, Mg, P, Na, Fe and Cu) in quantity larger than that evaluated in RM-BX, whereas RM-BX have Zn and Mn levels higher than those found in SM-BX. Phytochemical analyses showed that RM-BX exhibited total phenolic and flavonoid contents higher than those measured in SM-BX. Consequently, RM-BX presented an antioxidant activity higher than that of SM-BX: 2.85-fold ABTS radical cation scavenging capacity and 1.9-fold oxygen radical absorbance capacity. Finally, RM-BX and SM-BX were greatly safe since, at concentration up to 100 μg/ml, they did not modify the viability of neutrophils as determined by flow-cytometry assay using Annexin V-FITC/Propidum Iodide as markers. In conclusion, our in vitro studies indicate that both red and sugar maple bark extracts have a real potential as food additives.     

Forecasting Apple Fruit Color Intensity with Machine Learning Methods

In this study, we focused on the possibility of forecasting the development of skin color in apples on the basis of weather forecast by using a machine learning methods. We used supervised learning and generated models via the use of six decision trees. The purpose of the research was to build models that would allow for in-practice-acceptable accuracy in the prediction of the development of fruit skin color (especial a colour parameter a*), for three apple varieties. For cv. ‘Gala, Brookfield’, the most accurate models were generated by using decision tree J48 (89.13% accuracy). For late ripening cv. ‘Fuji, Kiku 8’ and cv. ‘Braeburn, Maririred’, the most accurate model was obtained by using decision tree LMT (91.73 and 96.65% accuracy). The data confirm that the applicability of predictive models strongly depends on the accuracy of weather forecasts. In regard to the seven-day weather forecast, which was used for expert models, the accuracy of the models was, on average, reduced by 10.73%.     

Multi Criteria Assessment of Zero Residue Apple Production

During the 2008–2010 growing seasons, an alternative ‘zero residue apple production system’ was compared with integrated apple production with cvs ‘Idared’, ‘Golden Delicious’, ‘Jonagold’ and ‘Gala’ in commercial orchards at several locations throughout Slovenia, using data envelopment analysis (DEA), and multi criteria assessment by an analytical hierarchical process (AHP). The principle of the ‘zero residue apple production’ is a combination of integrated (IP) and organic apple production. During the first 3 months of the growing season (1 April–30 June), pesticides used in IP with rapid degradation (8–10 applications) were used to control pests and diseases. During the second part of the season from 1 July to harvest, organic products (6–12 applications) were employed compared with 19–25 applications overall in IP. The goal of the alternative system was to reduce the amount of applied conventional pesticides by 40 % and to minimize pesticide residues in fruits to below the limit of 0.5 % of the legal maximum residue level (MRL) or below the residue concentrations of 0.005–0.01 mg/kg and to retain the high long-term level of yield, fruit quality, and net income per hectare. The number of pesticide residues was reduced from 4.2–5.5 in IP to 1.8–3.4 in zero residue cultivation, while 3 year average yields (class 1 fruit) were 4–9 % lower than in IP. The break even prices ranged from € 0.31 for Idared in IP, € 0.34 for ‘Elstar’ of both production systems to € 0.35/kg for zero residue cultivated ‘Golden Delicious’. Overall, a price increase of just € 0.02/kg for residue free apples would make this new ‘zero residue apple production’ profitable then representing a realistic alternative to the standard integrated apple production system.