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| Silicate fertilizers increase disease resistance of Poinsettia to fungal infections | |
| Researchers at Clemson University, South Carolina, have demonstrated the positive effect of supplementing macronutrients with Potassium and Calcium silicate to control the development of Botrytis cineria in Poinsettia mother plants and subsequent cuttings in propagation and storage. Potassium and Calcium silicate were applied as a drench or foliar spray at concentrations of 0ppm (control) 125ppm, 250ppm and 500ppm to Poinsettia varieties Peterstar ‘Red’ and Snowcap ‘White’. Leaf age did not significantly influence Botrytis development. Calcium and Potassium silicate applied at 250ppm and 500ppm were effective at reducing Botrytis infection. After innoculation of leaf discs, the disease incidence fell from between 50% and 75%* at 0ppm to between 20% and 25% at 500ppm. Calcium and Potassium silicate reduced losses to Botrytis in storage and propagation. The number of leaves infected during mist propagation fell from between 40% and 80% (at 0ppm) to between 0% and 7% at a 500ppm. The number of infected leaves of cuttings taken from treated mother plants and held at 5°C for 5 days, fell from between 60% and 85% (at 0ppm) to between 20% and 30% at 500ppm. The concentration of 250ppm proved the best, reducing the number of infected leaves to around 7%. (*These percentages ar indicative only). James E. Faust, Associate Professor, Losenge Turoop, Visiting Professor, Clemson University, South Carolina. E-mail:jfaust@clemson.edu www.floriculturealliance.org |
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