Selection of anti-wetting agents and photoprotectants compatible with a soybean weed control bioagent

Adjuvants incorporation at formulations can positively influence the performance of bioagent control, contributing to preservation of the inoculum until being used. Adjuvants should not be toxic to pathogen and tests that evaluate the sensitivity of biologic products are essential. The aim of this study was to analyze the compatibility of the anti-wetting agents microcrystalline cellulose, anhydrous sodium carbonate, magnesium oxide, talc, calcium carbonate, silicon dioxide, and photoprotectants NeoHeliopan® AV, NeoHeliopan® E1000, Eusolex® 6007, NeoHeliopan® Hydro, Tinosorb® M, Eusolex® 232 and a Complex filters UVA/UVB with the fungus Bipolaris euphorbiae, in order to select products to formulate a fungus-based bioherbicide. All products were used in concentrations of 0.01, 0.05, 0.1, 0.5 and 1%. After evaluating vegetative growth, sporulation, and germination, the products were toxicologically classified by calculating the biological index. The anti-wetting agents calcium carbonate, talc, microcrystalline cellulose, and silicium dioxide did not interfere in the development of the fungus, and were deemed compatible. The photoprotectant Tinosorb® M was classified as compatible with the fungus in all concentrations used, a similar outcome to Eusolex® 6007, except at 1.0% concentration. Most of the other photoprotectants were compatible in concentrations ranging between 0.01 and 0.1%, except for Complex filters UVA/UVB at 0.05% and NeoHeliopan® E1000 at 0.1%. NeoHeliopan® Hydro was rated moderately toxic to the fungus in all concentrations used. Conidial germination was less affected than growth and sporulation.  Key words: Bipolaris euphorbiae, biological control, bioproduct, formulation, adjuvants.