Influence of Bacillus Spp. Based Bioproducts on Potato Plant Growth and Control of Rhizoctonia Solani

Some Bacillus based bioproducts were analyzed for their plant growth promotion and Rhizoctonia solani biocontrol potential in potato plants. The bioproducts were formulated as concentrated aqueous suspension, each containing one of the following plant beneficial bacteria: Bacillus safensis Rd.b2, Bacillus spp. 75.1s and Cp.b4 strains. These were applied on potato seeding material in order to evaluate plant growth promotion effects. The biocontrol efficacy was also evaluated, using Rhizoctonia solani DSM 63002 as plant pathogen, and Prestige 290FS as reference chemical treatment.In the plant growth-promotion experiments, several biologic parameters were biometrically evaluated. Best results regarding plant growth and vigor were obtained using CropMax, a commercial phytostimulatory product. However, the bacterial treatment with Bacillus spp. Cp.b4 and 75.1s showed an improved plant growth compared to the untreated control. An efficacy of 93.75% against Rhizoctonia dumping-off was registered when using the Prestige 290FS chemical control. Mix treatments based on this pesticide, in low dose, combined with Cp.b4 or 75.1s biocontrol strains significantly reduced the pathogenic attack, showing 85 to 87.5% efficacy.The present research demonstrated that the bacterial bioproducts based on Bacillus spp. 75.1s and Cp.b4 strains increase plant growth and are highly effective in controlling Rhizoctonia attack in potato plants.