Silicon reduces Fusarium Head Blight Development in Barley

Silicon (Si) can directly or indirectly enhance plant resistance to fungal pathogens, but no report is available concerning the effectiveness of Si in decreasing Fusarium Head Blight (FHB) disease on barley (Hordeum vulgare L.).

The evaluation of Si supplied to barley incorporated into the soil and as a foliar spray against four FHB species under controlled conditions was investigated. In addition, the potential resistance mechanisms related to the reduction of Disease Incidence (DI) and Disease Severity (DS) measured at 7, 14, 21, and 28 days post-inoculation (dpi) were proposed. Four Si concentrations of both a SiO₂ powder incorporated into the soil as a solid source, i.e., of 0.00, 0.50, 1.50 and 3.00 g/kg and a liquid formulation of Si as a foliar spray, i.e., of 0.0, 0.8, 1.7 and 3.4 ppm were tested to study their effect on the development of FHB fungi on two barley moderately resistant “MR” and susceptible “S” cultivars.

All concentrations of Si did not significantly reduce DI and DS at 7 dpi. The disease reduction was observed with the application of 1.50 g/kg of soil and 1.7 ppm at 14 dpi and increased with time until 28 dpi, however, the other rates had no significant effect. At 28 dpi, solid and foliar treatments reduced DI by 26.6% and 22.9%, respectively, on “MR” cultivar, and by 19.4% and 19.5%, respectively, on “S” cultivar and decreased DS by 20.4% and 19.5%, respectively, on “MR” plants and by 18.8% and 18.4%, respectively, on “S” plants.

No effects of Si were observed during the initial infection stage; our results suggest that Si triggers defense processes in barley plants in the latest infection stages to diminish DI and DS by affecting mycotoxins synthesis. Si inputs can be a valuable tool in integrated FHB management by reducing the disease development on barley.