Control strategies: integrated analysis between adjuvants and spray volumes on the effectiveness of fungicides applied to wheat crops

Wheat productivity has been impacted by the presence and pressure of foliar and ear diseases. To mitigate the damage caused by these pathogens and improve the effectiveness of fungicide application, this study aimed to evaluate the effectiveness of different fungicides combined with different adjuvants and spray volumes in combating fungal diseases. Three field trials were carried out, using three cultivars, in the cities of Santa Maria, RS, and Getúlio Vargas, RS. The experiment followed a randomized block design with a factorial scheme (4 × 2 + 1). The factors consisted of fungicidal sprays with adjuvants (Mees™, Extremo®, Silwet AG®) and without adjuvants, and two spray volumes (50 and 100 L ha⁻1), besides a control without application (additional). The variables evaluated included the incidence and severity of diseases (yellow spot, leaf rust, and Fusarium head blight), tracer deposition in the ears (µg ear⁻1), hectoliter weight (kg hL⁻1), and grain yield (kg ha⁻1). The results showed that the use of adjuvants in fungicide sprays, especially organosilicone and vegetable oils, can increase wheat productivity and improve disease control compared to the absence of these products. For effective disease control, when using smaller spray volumes, it is essential to adopt a more technical approach, as well as to understand the interactions between adjuvants, the environment, and the phytosanitary product used.