Alternative budburst management in Campanha Gaúcha vineyards

Abstract Seeking a less toxic alternative to budburst management than hydrogen cyanamide, doses of the mineral-organic product Erger® were tested in combination with calcium nitrate (Ca(NO3)2). The experiment was conducted in Santana do Livramento, southern Brazil, during the 2013/14 and 2014/15 growth cycles, in a ‘Merlot’ vineyard conducted in a vertical trellis system, pruned in double Guyot, with SO4 rootstock. Treatments were: Control (unsprayed); 5.0% Ca(NO3)2; 2.5% Erger® + 5.0% Ca(NO3)2; 5.0% Erger® + 5.0% Ca(NO3)2; 7.5% Erger® + 5.0% Ca(NO3)2; 3.5% Dormex® (positive control). All Erger® treatments stimulated budbreak, increasing budburst from 68% (unsprayed and calcium nitrate means) to 83% (Erger® means) in the first cycle and from 85% to 96% in the second one, with no difference among doses. Plants treated with Dormex® had budburst similar to Erger® in the first cycle (85%), but budburst in the second cycle was only 72%, possibly due to burned buds. Therefore, Erger®, in concentrations of 2.5% or more with 5% calcium nitrate, may be a promising alternative to induce budburst in regions with restrictions in cold availability.