Effect of potassium silicate on epidemic components of powdery mildew on melon

Despite the differences in Si distribution related to how PS was applied to the plants, root and foliar applications affected all the epidemic components compared to the non-Si control treatment, except for the LP. However, the effects of PS application on roots were more pronounced since it resulted in greater reductions of RC, CA, and conidial production than foliar application. The effects of both forms of PS application on the epidemic components correlated with lower values of AUDPC, and the effect on this variable was greater when PS was supplied to the roots. The differences in the rate of colony expansion (rc) probably effected AUDPC and not conidial production per colonized area due to the short period during which the evaluations were made (20 days), which reflected the effects of only two extra disease cycles assuming a latent period of 6 days. The effects of Si applied as potassium silicate (PS) on epidemic components were evaluated in two September 2008 and April 2009 trials. The source of PS was the commercial product Sili-K (Unaprosil), which is composed of 15% K2O (210 g L−1) and 12·2% soluble Si (171 g L−1). The product was applied by spraying all leaves (foliar treatment) or through irrigation water (root treatment). The control treatment consisted of plants sprayed with water only. The three treatments were arranged in a completely randomized design with eight replications, each consisting of a single pot containing two plants. For foliar application, PS was applied at 30 mL L−1 (pH 10·2), 24 h before inoculation, as a fine mist on the upper surface of the leaves until runoff using a 0417·02·00 model handheld manual sprayer (Guarany). For the root treatment, pots were irrigated daily with 250 mL PS solution diluted in deionized water at a final Si concentration of 2 mm (0·34 mL L−1 of PS) with the pH adjusted between 5·5 and 6·5 using NaOH (1 m) or HCl (1 m) as necessary. In order to normalize the amount of potassium supplied to plants in the root treatment, plants from the foliar and control treatments were irrigated daily with 250 mL 1·53 mm KCl (Sigma-Aldrich) solution with the pH ranging from 5·5 to 6·5 and adjusted as described above. If you are looking for high quality, high purity and cost-effective Potassium silicate, or if you require the latest price of Potassium silicate, please feel free to email contact mis-asia.

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