Antagonistic effect in vitro of three commercial strains of Bacillus sp. against the forest pathogen Diplodia corticola

Abstract

Botryosphaeria canker is a major threat for Mediterranean forests since it causes severe economic and ecological impacts in productive cork oak (Quercus suber L.) stands in western Europe. The disease is caused by the fungus Diplodia corticola A.J.L. Phillips, A. Alves & J. Luque [Ascomycota, Dothideomycetes, Botryosphaeriaceae; formerly misidentified as Diplodia mutila (Fr.) Mont. (Alves et al., 2004)], causing severe dieback in mature Quercus spp., with necrosis in the stem and branches, and mortality of seedlings. The host range of the pathogen includes several Mediterranean oak species such as Quercus canariensis Willd., Quercus coccifera L., Quercus ilex L. and Q. suber. In cork oak, the pathogen causes branch necrosis and canker in the phelloderm exposed by debarking, which severely limits cork production, reduces the value of the extracted cork and severely reduces the vigour of the infected trees (Luque et al., 2008). The disease has been traditionally treated using chemicals such as benomyl (C 14 H 18 N 4 O 3 ; Benlate/WP, Du Pont Ibérica, S.A.) and thiophanate-methyl (C 12 H 14 N 4 O 4 S 2 ; Pelt/SC, Aventis CropScience España). Nevertheless, European policies for forest management advise against the use of fungicides; the use of benomyl is banned whereas thiophanate-methyl use was permitted until October 2020.As a consequence of these policies, the development of new control methods that reduce or even replace the use of chemicals is urgently

Evaluación in vitro e in vivo de Bacillus spp. como agente de control biológico en el escaldado del alcornoque

“…Durante el desarrollo del ensayo in vitro se midieron los radios representativos del crecimiento micelial hacia el tratamiento aplicado encima de un disco de papel estéril, mediante los cuales se calcularon un total de cinco índices de antagonismo: c (cm), Sc (cm), I (%), AI (%) y DAI (%) (Campanile et al, 2007;Martínez-Álvarez et al, 2016;Muñoz-Adalia et al, 2021). Asimismo, se evaluó la tasa de esporulación del hongo en cultivo dual, pasados treinta días desde la inoculación (tres réplicas para cada tratamiento y cepa; n=73) mediante conteo de conidios en cámara Thoma.…”

“…(Dimopoulou et al, 2021;Raaijmakers et al, 2002;Raupach & Kloepper, 1998;Raza et al, 2016 ;Zhang et al, 2016). Pese a la existencia de algunos estudios que prueban su eficacia frente a patógenos forestales (Dai et al, 2021;Muñoz-Adalia et al, 2021), la investigación en este campo se encuentra aún en una fase incipiente por lo que es necesario seguir profundizando en la efectividad del agente empleado en condiciones de campo.…”