Five isolates of Penicillium citrinumwere isolated from casing soils, copmpost and fruiting bodies of Agaricusbisporus from several culture stations in Iraq. According to the pathogenicity test, the highest percentage of inhibition was recorded for isolate P.citrinum(B1). The causal agent was molecularly diagnosed to the level of P. citrinumaccording to the nucleotide sequence analysis of the ITS genome region and it was recorded globally on the NCBI data base under the accission number ON738710.1.The effect of the hot aqueous extract of cloves and conocarpus, and the efficacy of the biocide VEROX on the production and phenotypic characteristics of the white edable fungus Agaricusbisporus was studied with the presence of the pathogenic fungus. The results showed that the treatment of the combination of plant extracts + biocide + pathogenic fungus led to the highest rate of growth inhibition of the pathogenic fungus, increasing number of fruiting bodies up to 435 compared to the control treatment of pathogenic fungus 140. The total yield of the same treatment was 16.398 kg compared to 3.343 kg in the control treatment, and the biological efficiency was recorded by 37.2% compared to 10.2% in the control treatment. In general, this combination led to an increase in production and an improvement in the qualitative characteristics of the fruiting bodies, as the average diameter of the cap was 40.6 mm and the stalk length was 37.3 mm compared to 27.8 mm and 23.5 mm in the control treatment, respectively.