Relative efficiency of silicon sources on rice leaf blast control

Abstract

Silicon fertilization of rice is one of the alternatives for reducing the use of fungicides in the control of rice blast. An experiment was conducted, during 1999/2000 and repeated in 2000/2001, in order to study the efficiency of sources of silicon (Si) to reduce leaf blast on rice cultivar Metica-1, cultivated in the low land. The treatments included three sources of Si (high furnace silicate slag, serpentinite ore rich in silicon and wollastonite ore, a native calcium metasilicate) at five doses (0, 0.5, 1.0, 2.0 and 4.0 Mg ha^-1), with and without fungicide treatment (pyroquilon 200 g a.i. per 100 kg of seed). The blast disease severity decreased with increase in Si doses. The relationship between area under disease progress curve and doses of silicate slag as well as wollastonite were linear and negative, with and without seed treatment. Furthermore, the results show the increased efficiency of seed fungicide treatment in reducing blast severity, with silicon fertilization.