Sclerotium rolfsii survival after autumn biodisinfestation in southeastern Spain

M. Ojinaga, M.M. Guerrero, C.M. Lacasa, V. Martinez, S. Larregla
The effect of biodisinfestation (soil amended with organic matter and tarped with a transparent plastic film) with mild temperatures was evaluated in Sclerotium rolfsii survival in a pepper greenhouse located in Murcia (southeastern Spain). The treatments tested were: T1: wheat kernel shell + fresh sheep manure (WKS+FSM) 3.5 kg m‑2; T2: sunflower seed cake + fresh sheep manure (SSC+FSM) 3.5 kg m‑2; T3: fresh sheep manure (FSM) 3.5 kg m‑2; and T4: control without amendment and without plastic. The biodisinfestation was initiated in October and treatments were carried out for 6 weeks. Treatments were randomized in a complete block design with three replicates. The soil temperature and soil oxygen content were measured during the application of biodisinfestation treatments. Viability of sclerotia of Sclerotium rolfsii, buried at 15 and 30 cm soil depth, was determined before and after the application of treatments. Sclerotia viability was determined by sowing them in a selective agar medium followed by subsequent observation of sclerotia germination with a stereoscopic microscope (×60 magnification). Soil temperature did not exceed 38°C during the biodisinfestation treatment. Soil oxygen content was below 2% in the biodisinfestation treatments while in the control treatment was always close to 16%. Anaerobiosis was longer in the biodisinfestated soil with the SSC+FSM amendment (oxygen <2% up to 28 days) than with the WKS+FSM amendment (oxygen <2% up to 16 days). All biodisinfestation treatments reduced sclerotia viability when compared to the non-treated control. The order of amendments effectiveness was T2 (SSC+FSM) > T1 (WKS+FSM) > T3 (EFO). The above-mentioned amendments reduced inoculum survival (expressed as germinated sclerotia) with respect to the control treatment 54-59, 52-55 and 40-54% at 15-30 cm soil depth, respectively.
Ojinaga, M., Guerrero, M.M., Lacasa, C.M., Martinez, V. and Larregla, S. (2025). Sclerotium rolfsii survival after autumn biodisinfestation in southeastern Spain. Acta Hortic. 1416, 353-360
DOI: 10.17660/ActaHortic.2025.1416.46
https://doi.org/10.17660/ActaHortic.2025.1416.46
southern blight, sclerotia, organic amendment, anaerobic soil disinfestation, soil biosolarization, Capsicum annuum
English

Acta Horticulturae