Suppressive effect of potassium silicate on powdery mildew of strawberry [Fragaria ananassa] in hydroponics
2004
Kanto, T. (Hyogo-ken. Technology Center for Agriculture, Forestry and Fisheries, Kasai (Japan)) | Miyoshi, A. | Ogawa, T. | Maekawa, K. | Aino, M.
From 1996 to 1997, potassium silicate (SiO2) was tested at 0, 25, 50, and 100mgl sup(-1) in hydroponics to control powdery mildew. Other elements were added in the usual amounts, and the strawberries were cultivated hydroponically in a greenhouse for 4 months (from October to January). The powdery mildew spread in the control plot, but little mildew developed in the plot with 25mgl silicate, and none in plots with more than 50mgl sup(-1) silicate. The suppressive effect lasted for about 4 months on fruits and even longer on leaves. On analysis of mineral content in the leaves, only the silicate content differed markedly between the control and treated plants. Nitrogen, phosphate, potassium, and calcium contents did not differ greatly. The maximum silicate content was about 24 times that of the control, and disease severity decreased significantly when the content was more than 1.5% in the leaves. The hardness of the strawberry leaves, measured by a creep meter, was increased by the silicate treatment.
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