Soil fungicides to control soil-borne diseases of Mediterranean crops grown under greenhouse

J.A. Pascual, M.M. Rozas, M.A. Diez Rojo, M. Ros
Plant-parasitic nematodes and fungal diseases entail loss of crop in Mediterranean areas. To maintain economically viable production of crops, application of control treatments is often necessary. Increased environmental awareness is leading to more restrictions on the use of certain fumigants due to their impact on human health and soil system. It is therefore necessary to evaluate alternative treatments, which are less hazardous. Two experiments under greenhouse conditions were set up to evaluate the effect of alternative fungicides/nematicides to 1,3-dichloropropene (1,3-D), or metam sodium (MS). Specifically, this included testing the plant extracts of Liquidambar spp. (LQ) and Larrea spp. (LR)), the non-fumigant nematicides Oxamyl (OX) and fenamiphos (FEN) and dimethyl disulphide (DMDS), for the control of Meloidogyne spp. and soil borne-pathogens in melon and pepper plants. Crop yield and nematodes incidence were measured, and we assessed the abundance of Meloidogyne spp. and soil fungal pathogens by qPCR. Also, it was necessary to evaluate their potential effects on non-target soil microbiota, by measuring soil microbial activity, abundance and community composition. DMDS reduced populations of Meloidogyne spp. and the most important fungal pathogens (Rizoctonia solani and Fusarium oxysporum) and resulted in similar yields to 1,3-D. The plant extracts LQ and LR showed no nematicidal or fungicidal effect compared to MS. However, a promising alternative could be a mix of LR and MS, which may reduce the amount of MS needed to control fungal soil-borne pathogens (Fusarium spp., Pythium spp. and R. solani) as well as Meloidogyne spp. while providing similar pepper yield. Non-target soil communities in the LR+MS, and MS treatments were different from those in the plant extracts treatments, and more similar to control. However, fungal and bacterial community composition were affected to a lesser extent in the LR+MS compared to the MS treatment.
Pascual, J.A., Rozas, M.M., Diez Rojo, M.A. and Ros, M. (2020). Soil fungicides to control soil-borne diseases of Mediterranean crops grown under greenhouse. Acta Hortic. 1268, 179-186
DOI: 10.17660/ActaHortic.2020.1268.23
melon plants, pepper plants, Meloidogyne spp., fungal pathogens

Acta Horticulturae