Effects of Silicon on Development and Controlling of Powdery Scab in Irish Potato (Solanum tuberosum)

Abstract

Effects of different silicon levels on plant height, stem diameter, disease incidence and severity and its activity on polyphenol oxidase and peroxidase enzymes on powdery scab caused by Spongospora subterranean on Irish potatoes (BP1) was assessed. This was a greenhouse study at the University of Zimbabwe Crop Science department. A mixture of 50% sterilised vermiculite and 50% sterilised sand was used as growing media. 0, 250, 500 and 750ppm silicon concentrations were used. Irrigation water, other fertilizers and insecticides applied were made uniform across all treatments. Variations among treatments were monitored from three weeks after planting then on weekly basis for the coming eighty weeks. Silicon concentrations showed significance difference (p<0.001) on plant height and stem diameter of Irish potatoes. It proved to play a significant role in the growth of the potato plants. Silicon levels showed no significant difference on powdery scab incidence with all plants getting diseased. Silicon reduced the infestation severity at high concentrations. It also increased the activity of polyphenol oxidase and peroxidase enzymes in potatoes at different response rates. Results from the study indicates great potential of silicon based fertilizers in controlling powdery scab as well as growth rate of Irish potatoes.