**5. Conclusions**

Almost always, flame-suckering led to a significant reduction in suckers in each year of application, even if suckers flamed one time at the 12–13 BBCH growth stage (FlamingA) did not show a reduction in the initial number of suckers in 2017 and 2018 (Table 2). On the other hand, flaming when suckers were at the 15–16 BBCH growth stage (when vine main shoots were at the 18-19 BBCH) (FlamingB and FlamingC) were the most effective flaming treatments, thus suggesting that delaying flame suckering reduces the number of suckers that resprout. Double-flaming (FlamingC) significantly reduced the number of suckers compared to hand-suckering alone in 2016, suggesting that the time when suckers are removed is probably more important than the number of flaming treatments. Moreover, conducting flame-suckering only once reduces by half the total cost per use. Flame suckering thus seems to be a valid alternative to the use of chemicals for organic growers. In addition, the number of suckers removed by flaming was similar to that of manual suckering. This is an important outcome, because hand suckering is very expensive (e.g., about 10 € h−<sup>1</sup> for a labour time up to 60–70 h ha−1). Future studies could investigate the simultaneous use of flaming for both suckering and weed control, in order to provide an economic, sustainable alternative to a chemical approach for organic grapevine growers.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2073-4395/9/3/147/s1, Video S1: Flame suckering applied on 21 April 2016 at the 12–13 BBCH sucker growth stage.

**Author Contributions:** Conceptualization, M.R., L.M., C.F., M.F., A.P. and C.D.; methodology, M.R., L.M., C.F., M.F., A.P. and C.D.; validation, L.M., M.R., C.F., M.F., A.P., and C.D.; formal analysis, L.M., M.R., C.F., M.F., A.P. and C.D.; investigation, L.M., M.R., C.F., M.F., A.P. and C.D.; resources, L.M., M.R., C.F., M.F., A.P. and C.D.; data curation, L.M.; writing—original draft preparation, L.M.; writing—review and editing, L.M., M.R., C.F., M.F., A.P. and C.D.; visualization, L.M., M.R., C.F., M.F., A.P. and C.D.; supervision, L.M., M.R., C.F., M.F., A.P. and C.D.; project administration, M.R., L.M., C.F., and C.D.

**Funding:** This research received no external funding.

**Acknowledgments:** This study was self-financed by the Department of Agriculture, Food and Environment of the University of Pisa (Pisa, Italy). The authors would like to thank Adrian Wallwork (e4ac.com) for providing the English language editing of this paper; Valentina Panicucci from the Department of Agriculture, Food and Environment of University of Pisa (Pisa, Italy) for her contribution to the 2016 experiment; Piergiorgio Castellani from Castellani Spa (Pontedera, Pisa, Italy) for hosting the trials; and Alessandro Moretto from Castellani Spa, Paolo Belluomini and Piero Puntoni from the Department of Agriculture, Food and Environment of University of Pisa for their technical support.

**Conflicts of Interest:** The authors declare no conflicts of interest.
