Interaction between earthworms and entomopathogenic nematodes: impact in the soil community and plant performance

Soil ecosystems host diverse macro and microorganisms essential for terrestrial processes. Earthworms (EW) play a vital role in soil health by enhancing aeration, porosity, and nutrient cycling. Entomopathogenic nematodes (EPNs) such as Steinernema and Heterorhabditis contribute to pest management by killing insects. Although EW and EPNs are generally directly or indirectly beneficial for plants, their interactions and effects on plant-soil systems remain poorly understood. This study aimed to assess the impact of EW and their CEx, alone or combined with EPNs, on soil-plant dynamics. Using tomato plants and field soil from a commercial tomato plantation, we investigated the following treatments: application of organisms (control -no application-, EW, EPN, CEx, and EPN-EW and EPN-CEx interactions) and time post-application (two and four weeks). Our methodology included plant growth assessment, EPN infectivity tests, soil properties, and Next-Generation Sequencing for bacterial community analysis. We performed the whole experiment independently twice. This study elucidates the intricate interplay between EW, EPNs, and plant-soil systems, highlighting their possible impact on plant growth and soil nutrient dynamics while emphasizing the importance of timing in assessing their interaction.