Allelopathic Effects of Three Herb Species on <i>Phytophthora cinnamomi</i>, a Pathogen Causing Severe Oak Decline in Mediterranean Wood Pastures

• Main Authors: Manuela Rodríguez-Romero, Belén Godoy-Cancho, Isabel M. Calha, José António Passarinho, Ana Cristina Moreira
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Forests
• Subjects: allelopathy; biocontrol; dehesa and montado’s herb species; <i>Phytophthora cinnamomi</i>; <i>Quercus</i> decline
• Online Access: https://www.mdpi.com/1999-4907/12/3/285

The ability of three herbaceous plants (<i>Diplotaxis tenuifolia</i> (L.) DC., <i>Eruca vesicaria</i> L. and <i>Raphanus raphanistrum</i> L.) from Iberian wood pastures to reduce <i>Phytophthora cinnamomi</i> Rands pathogen populations through allelopathic relationships is studied. The inhibitory capacity of their aqueous root extracts (AREs) on mycelial growth and production of <i>P. cinnamomi</i> reproductive structures is analysed <i>in vitro</i>. In addition, <i>Quercus</i> seedlings were grown in infested by <i>P. cinnamomi</i>-soils and with the presence or absence of allelopathic and susceptible herb species to the pathogen to assess the defensive chemical response of <i>Quercus</i> seedlings through their leaf phenolic compounds. Results show a strong inhibitory capacity of AREs on <i>P. cinnamomi</i> activity in vitro and a protective effect of these herb species on <i>Quercus</i> plants against <i>P. cinnamomi</i><i>in vivo. D. tenuifolia</i> would be especially suited for biological control in the pathogen suppression.