This paper discusses some aspects of introducing a new agricultural crop in Latvia – truffles Tuber spp. Truffles are mycorrhiza–forming mushrooms with edible fruit bodies developing in the upper layer of soil. In Latvia, there is a growing interest among farmers to start cultivate truffles. From several cultivated truffle species, the Burgundy truffle Tuber aestivum syn. T. uncinatum is the most suitable to cultivate in Latvia. There are both autochthonous and introduced tree species in Latvia, which are suitable for the Burgundy truffle cultivation and it is suggested to use Quercus robur, Corylus avellana, Tilia cordata and Fagus sylvatica. In order to find the regions in Latvia with the highest potential for successful Burgundy truffle cultivation, climate and soil characteristics had been co-analysed. By superimposing soil and climate maps of Latvia, the most suitable regions for truffle cultivation are situated in the central and southern part of the country. Considering the variability in soil composition even within regions in Latvia, it is thereafter also of great importance to investigate site-specific soil characteristics in order to find the most favourable grounds for truffle cultivation. Other truffle species which might be suitable for cultivation in the future are also discussed, as well as some general recommendations in establishing truffle orchards.

The epidemiology of barley yellow dwarf disease is highly complex, involving numerous interactions between the abiotic environment and the crop, virus and vector - components of the disease. Barley yellow dwarf is the most economically damaging virus disease of grass and cereal crops worldwide. The disease identified as BYD has been reported in all countries in Europe causing losses on barley and oats, wheat and maize; losses on grasses are recognized but more difficult to quantify. There are five different strains of viruses causing BYD disease and all of them induce similar symptoms of chlorosis and stunting in graminaceous hosts. This report represents an overview of system components and their interactions in the epidemiology of barley yellow dwarf disease. As the main components considered here are aphids - (the only vectors of these viruses), host plants and viruses causing BYD disease. Some aspects of interactions between these components are also discussed.