Use of potassium silicate for powdery mildew control in Eucalyptus benthamii seedlings

Abstract

The effectiveness of potassium silicate (K2SiO3) to control powdery mildew was evaluated in Eucalyptus benthamii seedlings. Four treatments were applied: sprays of K2SiO3 (4 mL L-1) for 7 days, K2SiO3 (4 mL L-1) for 14 days, fungicide epoxiconazole + pyraclostrobin (6 mL L-1) for 14 days and ultrapurified water for 7 days. The experiment consisted of a randomized complete block design with three replicates, each with 10 seedlings with 90 days old per plot. Inoculation was done by brushing spores of Oidium eucalypti, collected from infected E. benthamii seedlings, onto superior parts of healthy seedlings. It was measured the diameter of the root collar (DC) and height (H) of the seedlings at 120 and 150 days. After 150 days, severity of disease, fresh mass (MF) and dry mass (MS) of aerial part were determined. No statistically significant differences were observed in height increment of the seedlings, in H/DC and MS. Sprays of potassium silicate at 14-days intervals showed the best results in the increase of the DC, in disease control and the difference between MS and MF (p < 0.05). The use of potassium silicate at 14-days intervals can be a form of control of powdery mildew, favoring the seedling growth of E. benthamii.

doi: 10.4336/2012.pfb.32.69.93