ON THE FAUNA OF PHYTONEMATODES OF ANTHROPOGENICALLY TRANSFORMED BIOCOENOSES IN ARMENIA

Abstract

We have examined the fauna and structure of soil nematode communities in anthropogenically transformed biocoenoses of Armenia by example of two biotopes in Yerevan city – fruit and berry gardens, and woodland park area. Ecotrophic characteristics of the identified nematode groups was given, and population density for the most pathogenic groups was determined. Research was conducted in 2019 in the Dalma fruit and berry gardens, and woodland park area of the Hrazdan gorge of Yerevan. 167 soil samples were collected during the research in rhizosphere of 35 plant species. Soil samples were collected by standard methods for nematology. During the research, we identified 22 genera of Nematoda including 8 parasitic ones, belonging to 16 families and 6 orders. Ecotrophic structure of nematode communities in the mentioned biotopes was represented by 5 ecotrophic groups: bacteriotrophs – Rhabditis, Plectus, Cephalobus, Eucephalobus, Panagrolaimus, mycotrophs – Aphelenchoides, Aphelenchus, predators – Discolaimus,Mononchus, Mylonchulus, Clarcus, polytrophs – Dorylaimus, Eudorylaimus, Mesodorylaimus, phytotrophs: obligate and facultative parasites of plants – Helicotylenchus, Rotylenchus, Criconema, Macroposthonia, Xiphinema, Paratylenchus, Pratylenchus, Tylenchus. Plant parasitic nematodes (8 genera) were represented by the most diverse generic structure. Among them Xiphinema, Helicotylenchus, and Macroposthonia were found everywhere. However, high density of these Nematoda population was found in rhizosphere of fruit and berry crops in the Dalma gardens. The highest number of Xiphinemahas was detected in rhizosphere of grape (Vitis vinifera) – (147 specimens per 100 cm3 of soil), Macroposthonia in rhizosphere of fig (Ficus carica) – (178 specimens per 100 cm3 of soil) and grape (Vitis vinifera) – (185 specimens per 100 cm3 of soil), and Helicotylenchus in rhizosphere of apricot (Prunus armeniaca) – (250 specimens per 100 cm3 of soil). Bacteriotrophs and polytrophs were the next prevalent trophic groups of nematodes. The highest density of their population was detected in rhizosphere of ornamental plants in the Hrazdan gorge.