ISHS Acta Horticulturae 450: International Symposium Growing Media and Plant Nutrition in Horticulture
SOME EFFECTS OF SILICATE ON PYTHIUM DAMPING-OFF OF CUCUMBERS IN POTTING MIXES (REFEREED) |
| Authors: | S. Jeffery, E. Williams, C. Whicker, C. Khoo, B. Summerell, C. Offord, P. Fahy, D. Noble |
| Keywords: | Pythium ultimum, Cucumis sativus, soluble silicon, disease suppression |
| Abstract:
Sodium silicate added to a composted seedling mix and a mineral-based propagation mix, at approximately 100 mg/l SiO2 in the mix solution, did not suppress damping-off of cucumbers caused by Pythium ultimum in the composted medium, when the pathogen was present in the mix prior to germination. This contrasts with reports of reduction of Pythium diseases in hydroponically grown cucumbers. There appears to be a minimum time for accumulation of silicon by seedlings, to obtain protection from challenges by pathogens. Supplementation of organically-based seedling mixes with silicates may not confer protection to seedlings during germination, but there is opportunity to examine the protection of older plants with silicate supplements, provided due attention is given to maintaining the required concentrations on a continuous basis to overcome leaching. Damping-off did not occur in the mineral-based medium, probably due to its physical characteristics which suppressed microbial activities, rather than other factors. | |
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