Brassica-based seedmeal biofumigation to control Phytophthora cinnamomi in the Spanish “dehesa” oak trees

Abstract

Phytophthora cinnamomi causes a highly destructive root rot that seriously affects oak trees in semi-natural woodlands known as “dehesas”. Biofumigation with Brassica spp. is a promising tool for disease management. We demonstrated that ground seeds from B. carinata and B. juncea can inhibit mycelial growth and decrease chlamydospore viability of P. cinnamomi in soil. In contrast, B. napus seedmeals were ineffective. Reduction of root necrosis in Lupinus plants was also achieved when soils were biofumigated with B. carinata or B. juncea seedmeals. Seedmeal effectiveness was strongly correlated with high sinigrin (2-propenyl glucosinolate) content. We conclude that biofumigation with seedmeals rich in sinigrin could be effective as part of integrated management of oak disease caused by P. cinnamomi in “dehesas”.