Organic viticulture and alternative strategies to conventional tillage favor the occurrence of organisms that act as biological control agents in the vineyard

According to a doctoral thesis defended at the University of La Rioja, organic viticulture and specific soil management practices alternative to conventional tillage favor the presence and activity of native entomopathogenic nematodes (EPNs) in the vineyard, enhancing the ecosystem service that these organisms provide as biological control agents.

This is one of the conclusions of Rubén Blanco Pérez's Ph.D. thesis, entitled 'Effect of alternative viticulture on native entomopathogenic nematodes and other organisms linked to their soil food web in DOCa Rioja vineyards', defended at the University of La Rioja (UR) with international mention and the highest qualification.

The research of the UR new doctor shows that alternative strategies to traditional viticulture benefit the community of native EPNs, beneficial soil agents of significant relevance for the agroecosystem, primarily in biological control programs against various arthropod pests.

Developed at the Department of Agriculture and Food -under program 783D Oenology, Viticulture and Sustainability (Royal Decree 99/2011)-, the thesis is part of the Interuniversity Doctoral Program in Oenology, Viticulture, and Sustainability of Campus Iberus. The Ph.D. thesis has been directed by UR professors Vicente Santiago Marco Mancebón and Ignacio Pérez Moreno and the researcher Raquel Campos Herrera at the Institute of Vine and Wine Sciences (ICVV, Spanish National Research Council, SCIC).

During the development of the thesis, the researcher combined traditional (insect-bait bioassays) and molecular (real-time PCR analysis) techniques in three independent studies.

Thus, he first analyzed the EPN occurrence in vineyards with cover crops seeded with Bromus catharticus, a mixture of floricultural species, and spontaneous vegetation. Furthermore, he studied 80 vineyards distributed throughout the DOCa Rioja to evaluate the effect of cover cropping and organic viticulture compared to conventional practices.

Finally, he studied vineyards with different types of organic mulches (based on pruning debris, straw, and mushroom post-harvest compost) to compare them to others with conventional tillage and herbicide applications.

After analyzing the data, the thesis states that, overall, the EPN occurrence and activity were significantly higher for organic viticulture and specific types of cover crops and organic mulches, particularly for spontaneous vegetation and post-harvest mushroom compost mulches.

In addition, during the evaluation of entomopathogenic activities through insect baiting, the researcher was able to identify, isolate, and characterize a new EPN species named Steinernema riojaense.

Rubén Blanco Pérez's thesis is part of the research and training work carried out by both the ICVV and the University of La Rioja, which is aligned with the research areas promoted by the strategic project Enorregión, launched by the Government of La Rioja to transform the entire wine value chain. One of the key lines promoted by Enorregión is the use of innovative sustainable practices in viticulture and winemaking processes.

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