Abstract
This work was designed to study the efficacy of two types of silicon compounds (sodium silicate and potassium silicate) to control charcoal rot disease caused byMacrophomina phaseolina in vitro, under greenhouse and field conditions.In vitrostudy showed that sodium and potassium silicate at all concentration were effective on inhibiting the growth of the pathogen. Generally, sodium silicate significantly reduces pathogen growth than potassium silicate (29.02% and 19.34%, respectively). Under greenhouse conditions, treatments with sodium silicate caused the highest percentage of disease reduction of charcoal rot disease (37.8%), compared with infected control plants. Sodium silicate treatment increased the root, stem and leaves thickness layers of cortex (CO) and pith (PI) compared to untreated soybean plants. Under field conditions, application of sodium silicate in controlling charcoal rot disease showed significant reduction of disease severity in both tested seasons (56% and 42%, respectively) as well as increased the yield of soybean by (136.7% and 97.6%, respectively). The study concluded that application of sodium silicate could be useful in reducing charcoal rot diseases under greenhouse and field conditions.