Search

Nowadays, in sustainable agriculture growing winter cover crops and using organic manure have been widely implemented to improve soil quality which leads to increase of microbial activity. Six-year study was performed to evaluate the effect of cropping system on soil microbial hydrolytic activity, content of soil organic carbon (SOC) and total nitrogen (Ntot) under potato cultivation by considering various management systems, while comparing the soil parameters after previous crop. The experiment consisted of five-field crop rotation with two different organic (Org 0 as control and Org II with winter cover crops plus added composted manure) and conventional (Conv 0 as control and Conv II with mineral N, 150 kg ha–1) farming systems. The results showed that hydrolytic activity of soil microbes decreased in every farming system under potato cultivation. Interestingly, after potato cultivation, the lowest and highest decrease in the soil microbial hydrolytic activity were seen in Org II and Conv II systems, respectively. The highest soil microbial hydrolytic activity was measured in system Org II where incorporation of biomass from winter cover crops and cattle manure was used. Finally, SOC and Ntot were higher in organic farming systems and there no significant changes after potato cultivation. [ABSTRACT FROM AUTHOR]

Before its establishment in Estonia at the beginning of the twenty-first century, the Colorado potato beetleLeptinotarsa decemlineataSay was a notifiable quarantine pest for many years. In high-latitude environments it encounters strong evolutionary pressure to adapt to low temperatures due to high overwintering mortality and periodic influx of new individuals from more southern populations. Our study focused on gathering evidence for such a range shift leading to the formation of a permanent local population. The phenology and overwintering success of beetles was investigated from 2008 to 2015. Depending on weather conditions in the different years, the overwintered beetles emerged from the soil from the beginning of May to mid-June. Over 700 degree days accumulated in 2010, 2011, 2013 and 2014 exceeding the limit needed for development of two generations. However, food supply and temperature distribution in the growing period enabled development of the second complete generation only in 2010 and 2013. Survival of overwintering beetles in field conditions varied between 18% and 47% in the different years. Winter mortality was not associated with low air temperature in any year as snow cover provided the necessary protection and winter soil temperatures at the depth of 30 cm remained at around 0°C for the duration of the whole observation period, with only some records as low as −3.5°C. The survival of overwintering beetles is more likely defined by factors other than low temperature. As a result of periodic invasions of beetles with naturally lower cold resistance originating from southern regions, the structure of the overwintering population in Nordic temperate conditions is not homogeneous. Moreover, this may also be derived from cultural practices, as commercial producers regularly apply agrochemicals while organic growers avoid them. [ABSTRACT FROM PUBLISHER]

We have established for the first time that Colorado potato beetle (CPB) (Leptinotarsa decemlineataSay) (Coleoptera: Chrysomelidae) produced a distinct second generation in 2010 in Estonia. This species has a history, in Estonia, of less than 50 years. Due to their great ability to adapt to variable environmental conditions, the beetles spread very quickly throughout the country and established a permanent population in the 1980s. Before 2010, CPB has been predominantly univoltine. The occurrence of the second generation was the result of rare coincidence of extremely favourable weather as the cumulative degree days (DD) of 927 exceeded the sum needed for two full generations. Constantly high temperatures from the beginning of May caused the formation of summer generation adults already by the end of July and the long day photoperiod, as well the availability of fresh food, kept the beetles in reproductive mode preventing the onset of diapause. Summer beetles continued to oviposit up to the second half of September, but a large proportion of the second generation was eliminated from the population in the pre-adult or adult stages as they failed to end their development in the favourable period. Successful overwintering with about 50% survivors occurred only in association with completed development which was restricted to August and the beginning of September. An abundant second generation has potential to reduce primarily the yield of late potato cultivars. However, the unpredictable weather conditions in Estonia does not allow exact prediction of the appearance of a second generation. [ABSTRACT FROM PUBLISHER]

The use of synthetic pesticides is very common in conventional agriculture as plant protection measures and for improving storage of food. For increasing food safety, monitoring programmes are taking place in each European Union Member State and in Norway and Iceland every year. The monitoring aims to detect samples from food exceeding the maximum residue level (MRL) and provides data for an assessment of consumer exposure to pesticide residues. Results from Estonian national monitoring programme conducted by Veterinary and Food Board are presented in this paper, used to find out the differences in pesticide residue occurrences and MRL exceedances in local and imported food consumed in Estonia. In 2008, residues of one or more pesticides were found in 35–53% of the total analysed samples of fruits, vegetables and cereals. Imported food contained more pesticide residues compared to local food. MRLs were exceeded by 1.6% in 2008 and 2.3% in 2009 out of all samples, residues exceeding the MRLs were found in imported samples only. In 2010, 2.1% of total samples were above MRL. In 2011, 0.7% of total samples exceeded MRL which were of domestic origin. The highest MRL exceedances from the years 2008 to 2011 were propargite in beans with pods from Estonia over 10 times, chlormequat in grapes from India 7.9 times and trifluralin in tea from China 7.5 times. MRL was most frequently exceeded by dithiocarbamates, in 12 cases out of 22. The highest number of different pesticide residues in a single sample was 10 in apple from Belgium, 9 in mandarin from South Africa, 8 in strawberries from Spain and in apple from Poland. The results of monitoring programme show that local food contains less pesticide residues than imported food. By consuming food locally, it is possible to reduce the consumption of pesticide residues. [ABSTRACT FROM AUTHOR]

The effect of different mulches on carabid abundance and species composition was studied using pitfall traps in the Polli experimental raspberry plantation in the years 2001-2003 and 2006. Experimental treatments compared were: control - soil with no mulch and different mulch treatments - birch sawdust, milled peat, barley straw and black plastic. To estimate the potential role of carabids in raspberry beetle population regulation, the population dynamics of the dominant carabid species in relation to raspberry phenophases was determined. The activity density and species richness of carabids increased with plantation age and were influenced by mulching. In all study years, at the time of ripening of the raspberry fruits, when the raspberry beetle larvae leave the fruits to pupate in the soil, the most dominant carabid species were: Pterostichus vulgaris, Pterostichus niger, Carabus nemoralis and Harpalus pubescens. The barley straw mulch was significantly preferred to the other mulches by P. niger, P. vulgaris and C. nemoralis. H. pubescens did not exhibit a preference for a particular mulch. These four carabid species could be potential key predators of raspberry beetle larvae in Nordic plantations of perennial raspberry. [ABSTRACT FROM AUTHOR]

Blackcurrants are an important berry crop in many European countries. There is increasing demand for new and economically valuable blackcurrant cultivars suitable for organic production. To meet this demand, potential candidates of blackcurrant cultivars have been studied under Estonian field conditions. Our aim was to evaluate blackcurrant cultivars with regard to their productivity, berry quality, and resistance to the blackcurrant gall mite (Cecidophyopsis ribis Westw.). Our results showed that the drop of berries was the highest in the control treatment (no fertilizers used), and the lowest in conventional treatment. Higher yields were obtained from the conventional and organic treatments. The most productive cultivar, with the biggest berries and highest ascorbic acid content irrespective of cultivation system, was the cultivar 'Pamyati Vavilova'. Organically cultivated berries had a higher content of ascorbic acid than did conventionally cultivated berries. Minor damage by mites was observed on the cultivar 'Ojebyn'. We conclude that blackcurrant is a suitable crop for organic cultivation and that the cultivars 'Pamyati Vavilova' and 'Zagadka' respond well to organic cultivation. The cultivar 'Ojebin' is not considered to be well adapted for organic growing. [ABSTRACT FROM AUTHOR]