Abundance, diversity, and distribution of plant-parasitic nematodes in horticultural soils under different management systems in a tomato-producing area in Argentina

Abstract

Monitoring the diversity and structure of plant-parasitic nematode (PPN) communities together with developing appropriate control strategies can reduce the occurrence of these pathogens and other plant pests in horticultural crops. In this context a study of the abundance, frequency, diversity and distribution of PPN in horticultural soils under glasshouse conditions from the Green Belt of La Plata, Buenos Aires, Argentina, under different management systems was undertaken. Soil samples were collected from three horticultural areas with different tomato crop managements: agroecological crop (AC); organic crop with Brassicaceae soil amendments (OC); intensive conventional crop treated with methyl bromide (MeBr) (IC). The parameters evaluated were: nematode genera richness (G); Shannon-Wiener diversity index (H') (Hutcheson's t-test was applied for this index); equitability index (E); abundance; and frequency of genera. ANOSIM and SIMPER statistical analyses were performed to find significant differences between the nematode assemblages from the different sites. A total of 14 genera of PPN were identified among the three crop sites. Members of the feeding habits categories ectoparasites, semi-endoparasites, migratory endoparasites and sedentary endoparasites were observed. Statistical analysis enabled us to characterise each site based on the composition of the nematode assemblages. Helicotylenchus, Tylenchus and Nacobbus were the most frequent and abundant genera. AC and OC showed similar values of richness and diversity; the crop treated with MeBr (IC) showed the lowest diversity of PPN.