Effect of foliar-applied silicon sources on brown rot (Moniliniafructicola)

Abstract

The prevention of brown rot symptoms caused by Monilinia fructicola fungus in stone fruits is usually achieved by the repetitive use of chemical fungicides. However, foliar-applied silicon (Si) sources either alone or combined with fungicides, can be an effective alternative to reduce disease incidence, with beneficial cost and environmental impact. We carried out a set of experiments in field conditions with the aim of evaluating the effectiveness of foliar-applied Si sources, either in combination or not with fungicides, and applied at different phenological stages in preventing the brown rot occurrence in peach fruits. Three experiments were carried out in an 11-year-old Eldorado peach orchard, located in southern Brazil. Experiment 1 compared eight strategies in order to optimize the application timing. Experiment 2 was carried out to define the Si effect alone or combined with fungicides. Experiment 3 consisted of five treatments to verify the effect of different Si sources. The effects of the strategies in the pre and post-harvest brown rot incidence in fruits, fruit quality parameters and Si concentration in leaves and fruits were evaluated. Fruit anatomical investigation analysis was also performed. Si was effective in controlling brown rot in fruits. Six treatments with Si showed a similar effect compared to six fungicide applications. Si allowed a reduction of three fungicide applications, regardless of application period. Si foliar-treated trees revealed an increased leaf and fruit Si concentration. Si sources showed similar effectiveness in preventing the occurrence of brown rot incidence in fruits. Si represents a potential alternative in preventing brown rot incidence.