Effect of nitrogen fertilisation of strawberry plants on the efficacy of defence-stimulating biocontrol products against Botrytis cinerea

Abstract: Although Nitrogen (N) is a key component in many compounds implicated in hostpathogeninteractions, little is known on the possible effect of N fertilisation of the plant on theefficacy of defence-stimulating biocontrol agents. In the present work we examined the effect offive levels of N nutrition on the susceptibility of strawberry leaves to Botrytis cinerea and on theprotective efficacy of two biocontrol products presumed to induce plant defence mechanisms.Two days after the application of the biocontrol products, batches of leaf discs were excised,inoculated with B. cinerea and incubated in conditions conducive to disease development. Plantfertilisation had a highly significant effect on disease development for both strains of B. cinereatested and it significantly influenced the efficacy of the biocontrol products. Possible hypothesesand the relevance of these results for integrated protection are discussed.