Compatibilidade físico-química de misturas de fungicidas

Abstract

There are few studies about the physicochemical compatibility of pesticide mixture, which has great importance in the effectiveness of phytosanitary management and direct impact on the production costs of soybean crops. The objective of this work was to evaluate the physicochemical compatibility of fungicide mixtures commonly used in the management of soybean diseases, the main crop in the state of Mato Grosso do Sul. The methodology adopted followed the norms of the Brazilian Association of Technical Standards – NBR 13875:2014 for evaluation of physicochemical compatibility of pesticides and related compunds, through static and dynamic procedures. Three systemic fungicide (specific site mode of action) associated with protective fungicides (chemical multisite mode of action) and a foliar fertilizer were studied. Priori Xtra® (control), Priori Xtra® + Bravonil® 500, Priori Xtra® + Unizeb Gold®, Priori Xtra® + Manfil 800WP®, Priori Xtra® + Reconil® e Priori Xtra® + CuprozinUltra®. Score Flexi® and Elatus® compatibility were also studied associated with the same protective and fertilizer products. In all mixtures Ochima®, a penetrant adjuvant was added. Homogeneity, flocculation, sedimentation, phase separation, oil separation, crystal formation, cream, foam and lump formation were evaluated for all mixtures. The resulting mixtures had a pH value ranging from 5.00 to 8.34, characterized as weak acid and base solutions. In the static assay all mixtures with Bravonil® 500 had foaming and sedimentation except for Priori Xtra® + Bravonil® 500 mixture, pesticides that have the same formulation. Unizeb Gold® had sediment formation and phase separation in the 2h, 6h and 24h evaluations. Priori Xtra® + CuprozinUltra® mixture was partially flocculated, and the combination of Elatus® + CuprozinUltra® resulted in flocculation and lump formation. Associations in which Bravonil® 500, Unizeb Gold®, Reconil® and Manfil 800WP® products were present were sediment formation and phase separation, except for Bravonil® 500 which remained homogeneous. The other mixtures containing these products did not present perfect homogenization, mainly due to their formulation. In addition, the Elatus® + CuprozinUltra® mixture resulted in lumps. In the dynamic procedure all three systemic fungicides when mixed with Reconil® and Manfil 800WP® products were incompatible. Mixtures that showed incompatibility or some evaluated parameter should be tested in the field, evaluating their efficacy and possible cause of phytotoxicity.