Peter Tóth

Impact of natural enemies on Obolodiplosis robiniae invasion

The gall midge Obolodiplosis robiniae is a pest of black locust Robinia pseudoacacia. The species was recently introduced into Europe and it is nowadays a usual insect in Slovakia, where two-year field surveys were undertaken during 2007–2008. The main objective of this study was to determine the natural enemies attacking O. robiniae and estimate their influence on midge population, less than 3 years after its introduction. Eight parasitoids and bushcricket Tettigonia viridissima were responsible for midge regulation. The parasitoid complex was not typically that of an introduced species as it was predicted. Firstly, the midge was heavily influenced by a specialized parasitoid Platygaster robiniae, which was a predominant parasitoid and accounted for 98% of all specimens reared. Secondly, annual larval parasitism varied from 5.4 to 10.8%, though the late season average parasitism achieved 26.0% and often exceeded 40%. P. robiniae was also very efficient in exploiting galls and was capable of consistently regulating midge population. The surveys demonstrated that the average cumulative impact of natural enemies on the midge was substantial. Stably around 20% of attacked galls were recorded during the late summer. Bushcrickets were as efficient as parasitoids and played an important role at control, especially during lack of parasitoids. Greater impact of parasitoids was found in the larger settlements than it was in the countryside, when countertendency was valid for bushcrickets. There is an indication that O. robiniae parasitized by specialized parasitoid, and attacked by bushcrickets represents only a moderate risk for R. pseudoacacia or forest stands.

Spread of common ragweed (Ambrosia artemisiifolia L.) on arable land in the Žitný ostrov

Common ragweed (Ambrosia artemisiifolia) is an invasive alien species indigenous to North America. Ragweed is a big threat to agriculture and has a serious impact on human health. The most important area with ragweed occurrence within Europe is Pannonian Plain in Central Europe. This research introduces for the first time the unique, direct broad-scale survey of A. artemisiifolia in relation to real-life occurrence and infestation in the field. To understand the distribution of ragweed in the territory the geospatial analysis was applied to create 2D map in ArcGIS environment. The field survey was undertaken during summer 2014 in the Žitný ostrov (Slovakia). The investigation revealed that spatial occurrence of A. artemisiifolia is not homogeneous and there is also striking territorial heterogeneity of infestation rate. Ragweed was observed at 80 (47.2%) out of 169 sites. The infestation of arable land (mostly stubbles) varied from weak infestation, 24 sites (1-30 plants*10 m-2) to heavy infestation, 26 sites (˃80 plants*10 m-2). The research on associated plant communities was also carried out. Stubble field’s vegetation was found to be highly species poor, on an average only 2.5 species*10 m-2. Among 40 recorded species the most frequent (noticed at 25% sites) were Datura stramonium, Chenopodium album, and Mercurialis annua. This broad-scale survey provides an overview and useful information on considerations needed to make decisions about ragweed control and potential future expansion. The presented study offers also inventory of ragweed frequency over the large area.

Professional training in organic food production: a cross-country experience

Purpose The purpose of this paper is to characterize the agricultural activities and past experiences in professional training in the context of mobile learning in different countries (Portugal, Spain, Slovakia, Hungary, UK, Italy and Turkey). Design/methodology/approach For the survey, a questionnaire was prepared in English and Portuguese and then translated into the languages of the participating countries. It was delivered electronically for answering online by adults only. The participation was voluntary and in the end 133 consented valid questionnaires were obtained. For the treatment of the data, SPSS was used and basic descriptive statistics tools were applied, together with tests, namely, crosstabs and χ2 tests, considering a level of significance of 5 percent. Findings The results showed that the majority of the participants presently have some agricultural activity and one-third is thinking about starting one in the future. Most of the participants want to produce food organically, with significant differences among the countries studied in this paper. Most of the participants were enrolled in training activities in agriculture, especially those with higher education. This participation showed significant differences between countries as well as according to the dimension of the farms owned by the participants. A significant association was found between being a teacher in forming activities related to agriculture and being a farmer. When compared to distance learning, the training activities in classroom were the most frequent, with significant differences among the countries. Practical implications This study allowed characterizing the learning activities in the field of organic agriculture and established vision for planning of future training programs, in different countries, with maybe different social, educational and cultural realities. Originality/value Because the study included the participation of people from several countries all around Europe, the results obtained enrich the scientific area of training in organic farming, in view of distance learning vs classroom learning on a more global basis.

Designing training in organic farming on a multinational basis

Purpose – The purpose of this paper is to obtain information to characterize potential trainees seeking training programs about organic farming in the form of mobile learning. This information is expected to allow for establishing a set of guidelines to design mobile training opportunities that could match the potential clients’ wishes. Design/methodology/approach – For this survey an on-line questionnaire was used, translated into the languages of the participating countries (Portugal, Spain, Slovakia, Hungary, UK, Italy and Turkey), and in the end 133 consented valid questionnaires were obtained. The data analysis was made with SPSS and included basic descriptive statistics, crosstabs and χ2 tests, considering a level of significance of 5 per cent. Findings – The results obtained in the present study indicate that designing training programs in organic farming for a wide target population should attend to the differences between countries, which showed to significantly influence the preferences of the p...

Response of wild and weedy broomrapes to synthetic strigolactone analogue GR24

Parasitic plants of genera Orobanche and Phelipanche germinate after exposition to chemical signals exuded by roots of the host plants. The most studied germination stimulants belong to strigolactones (SLs), the newly discovered plant hormones which are stimulating hyphal branching of arbuscular mycorrhizal fungi and are involved in regulation of shoot and root architecture of plants. However, little is known about the effect of strigolactones on germination of non-weedy broomrapes. The objective of our study was to investigate the sensitivity of seeds of non-weedy broomrapes to synthetic analogue of SLs, GR24. The seeds of non-weedy broomrapes Orobanche alba, O. alsatica, O. caryophyllacea, O. elatior, O. flava, O. lutea, O. pallidiflora, O. reticulata, Phelipanche arenaria, P. purpurea and weedy species P. ramosa were collected in natural and cropland plant communities in Slovakia. Seeds of P. ramosa and P. purpurea were highly sensitive to GR24. On the other hand, effectivity of GR24 in inducing germination of several wild species, O. alba, O. caryophyllacea and P. arenaria was low, while the stimulant shown to be completely not effective on other non-weedy species O. alsatica, O. elatior, O. flava, O. lutea, O. pallidiflora, and O. reticulata. The results point out there are differences in the requirement for germination signals that possibly depend on the host.