Susceptibility of large-fruited hazel cultivars grown in Poland to major pest and their crop productivity

In Poland the cultivation of the hazelnut does not have a long tradition, but since the 1990's the production area has constantly increased and now the hazelnut is grown in over 1,000 ha, mostly in central-eastern Poland. The hazelnut cultivars grown in that region are old, mostly from the 19th Century, and are characterized by large, oval nuts, useless to the confectionery industry, but willingly bought directly by consumers. It should be mentioned that weather conditions in Poland are rather unfavourable for cultivating the hazelnut in comparison with warmer countries. However, according to the results of chemical analysis, nuts obtained in these conditions contain considerably less saturated fatty acids unfavourable to the human diet and more unsaturated fatty acids. As in some other countries, insect and mite pests are major detriments to hazelnut production in Poland and are the major concern for many hazelnut growers. Nevertheless, there are hundreds of pest species but only a few of them are common and cause economic damage. Among them, in Polish conditions, the most important are: nut weevil (Curculio nucum), filbert bigmite (Phytoptus avellanae), filbert aphid (Mywcallis coryli) and lecanium scale (Parthenolecanium corni). In the course of several years' research, the different susceptibility of chosen cultivars of large-fruited hazelnut to these pests was confirmed. The establishment of resistant varieties and their cultivation may lead to a reduction in the application of strong pesticides and the preparation of a hazelnut IPM program in our country. Moreover, the resistance of hazelnut cultivars to major pests in comparison with their crop productivity is discussed in this paper.