The invasive alien plant species in organic crops in Vojvodina

Based on the review of long-term studies (2008-2015) of weed flora in various organic crops in Vojvodina (cabbage, lettuce, soybean, onion, carrots, maize, marigold, dill, buckwheat, potato, basil, lucerne), a total of 88 plant species were found, 53 (60%) of which are alien (non-native). By analyzing the invasiveness status of alien taxa according to different categorizations, we highlight the presence of 14 invasive alien species (9 neophytes; 5 archeophytes). The presence of 4 taxa, considered invasive according to all of the categorizations analyzed, stands out: Ambrosia artemisiifolia, Conyza canadensis, Erigeron annuus and Galinsoga parviflora.However, according to the databases of invasive plants in the territory of Serbia, 6 more species, are considered invasive, namely: Amaranthus retroflexus, Datura stramonium, Echinochloa crus-galli, Portulaca oleracea, Sorghum halepense and Veronica persica, of which only E. crus-galli is categorized as highly invasive. Of all the taxa that are considered highly invasive in Serbia, only A. artemisiifolia (58%) and E. crus-galli (33%) are present in organic crops with a higher frequency of occurrence, meaning that the organic crops in Vojvodina currently do not represent the main refuge for these species. However, due to their exceptional ability to rapidly spread and occupy new spaces, continuous research of invasive plants is needed, not only of those which are categorized as such in Serbia, but also of those which are considered as invasive in the wider European region.