Stinging nettle (Urtica dioica Linnaeus) (Urticaceae) is a well known medicinal plant cultivated in some European countries for a long time. Because of its multiple usability (food, medicinal plant, feed, fiber), adventageous agrotechnical qualities and low demands for plant protection, its more extensiv utilization can be expected. However, du...ring cultivation from time to time little damages can be occurred on it. The aim of this paper is to show and estimate the most important arthropods (pests and natural enemies) of stinging nettle. Under the pests characterized in the paper according to the references the peacock and the small tortoiseshell are the most important species living on stinging nettle. Their individuals from time to time propagated can cause an important damage on nettle leaves in cultivated nettle stands or assemblages. On the base of a 12 year observation period (Gödöllő, Debrecen, 1998-2010) the following species have been observed: Psylliodes attenuata, Chrysomela fastuosa, Phyllobius pomaceus, Pleuroptya ruralis, Inachis io, Aglais urticae, Microlophium evansi, Microlophium carnosum, Aphis urticata, Dasineura urticata, Tritomegas sexmaculatus. Inachis io has been the only species which during the observation period did danger the stinging nettle stand. The other pest species have not threated even timely either the stinging nettle stand or a single plant. The number and diversity of natural enemies was rather low: running crab spiders (Philodromidae), tangle-web spiders (Theridiidae), crabbing spiders (Thomisidae), lacewings (Chrysopa perla, Chrysopa formosa), coccinellids (Coccinella septempunctata, Propylea quattuordecimpunctata, Adonia variegata), hoverflies (Episyrphus balteatus), earwigs (Forficula auricularia), scorpionflies (common scorpionfly (Panorpa communis) and European paper wasp (Polistes dominula) predominated.
Citrus flatid planthopper, a native insect to North America had for a long time a scarce economic importance there. However, being polyphagous made little damage on citrus trees and some ornamentals. In 1979 it was introduced to Italy where it established and spread quickly. It is now an invasive alien species continually spreading in South and... Central Europe causing considerable damage in fruit crops and various ornamentals. Present study shows the results of a series of observations carried out from 2011 to 2015 at a number of habitats in north of Hungary. The pest could be found at each habitat but the hedge, the tree row, the gardens and the orchard/vineyard were the most infested. Frequency and population density of Metcalfa pruinosa were considerable on Asteraceae, Cannabaceae, Fabaceae, Juglandaceae, Lamiaceae, Rosaceae and Sapindaceae. Typical vegetation could be functionally classified as ornamental plants, trees/shrubs, fruit plants, weeds and feral plants. Feral plants – some of them also invasive alien species – were found at each habitat. Plant species native to America were among them the most populated. As the hedgerows were neglected, and most gardens, orchards and vineyards abandoned, these are excellent conditions for the quick and long-lasting establishment of the pest as well as they may be reservoirs to infest cultivated fruit crops and ornamentals. The hedgerow was situated along a railway line. The length of similar hedges can be merely in Pest county several hundred km, which means M. pruinosa has plenty of opportunity for spreading along the railway and infest agricultural and ornamental cultures. On the surveyed alfalfa and maize fields, accidentally very few nymphs and adults were observed. Although, the population density of M. pruinosa was considerable on many hostplants, economic damage or yield losses could not be detected. Economic or significant damage was observed only on roses, raspberries and stinging nettle. This later is cultivated in Germany and Finland. The applied horticultural oil was efficient.
Vegetables play an important role in human health and have an important effect on the human diet. It is equally serious to improve the volume, the diversity and the year round equability of vegetable consumption. The stinging nettle (Urtica dioica L.) is an alternative vegetable crop and available from the beginning of Spring to the end of Autu...mn; therefore, it can improve both the diversity and the equability of vegetable consumption. The stinging nettle has a superb nutritive value, it is a prospinach and it can be cooked in many ways.