Study the role of silicon in strawberries and its possible role in control of strawberry powdery mildew

Abstract

Silicon has been shown to control a number of diseases. The physical effect of silicon on strawberry plants is unknown. Omex SW7 is a silicon based wetter, which is used in the application of potassium bicarbonate for the control of strawberry powdery mildew and previous studies suggested that this combination has given enhanced control of strawberry powdery mildew. There is evidence that leaf hairs involved in plant disease resistance. This project investigated the uptake of silicon from the silicon based wetter into strawberry plants. The physical effect of the silicon on leaf hair length and density was also investigated. Three concentrations of silicon were used and three different timings were used. Whilst the main study has used the variety Elsanta, other varieties have also been used. The plants were assessed on (a) silicon uptake over time, (b) the density of leaf hairs on upper and lower leaf surfaces, (c) the length of leaf hairs on the upper and lower surfaces, and (d) accumulation of silicon in fruit. The principal findings include enhanced levels of silicon in leaves and an additional level where there were multiple application of silicon. On leaves with higher silicon levels there was an increased density of leaf hairs and the leaf hairs were longer. Six months after treatment with silicon there were no enhanced levels of silicon in the treated plants when compared with untreated controls. Silicon accumulation was not found in harvested strawberry fruit after the application of different concentrations of silicon. The different varieties of strawberry used showed anatomical differences. Untreated leaves from Rhapsody had no hairs on the upper leaf surface, but a low density of hairs was observed after treatment with silicon