In an organic farm of Tenjo (Cundinamarca, Colombia) the effect of various materials prepared from chipaca (Bidens pilosa) and microbial isolates, on the incidence and severity of P. infestans in potato (Solanum phureja) were studied using a completely randomized design (CRD) with subsampling and eight treatments: flowers slurry, mixed slurry; actinomycete AC 12 (Streptomyces sp.), mix actinomycetes; isolation bacterial (Bacillus subtilis ); mixed bacteria (Bacillus subtilis and Burkholderia cepacia); fungus (Geotrichum sp.) and a control (sterile distilled water). The results showed rapid disease incidence, which was evident at 36 days after planting (dap) and reached 100% involvement at 52 dap, with no differences between treatments. The severity was statistically different only in the treatment of “purin of flowers”, which differed significantly from the control treatment between 56 and 70 dap (27.8,% less) which strengthens results of previous tests as a potential biocontrol product. Lower percentages of severity versus control (not significant) were also obtained with the treatments “slurry mixture” and “mixed actinomycetes”, between 60 and 87 dap.