Mahmoud, E.Y., Ibrahim M. M. and M. M. A. Khalefa
Plant Pathology Res. Ins., Agric. Res. Center, Giza., Egypt
Greenhouse and field experiments were conducted in 2008 and 2009 to study the effect of calcium sulfate (CaCO4) concentrations at 0.0., 200, 400, and 800 ppm by using two applied methods or/and seed soaking and plant sprayer on incidence of sesame and sunflower charcoal rot disease caused by Macrophomina phaseolina Tassi (Goid). Treated with CaCO4 showed a significant reduction on the percentage of linar growth and number of sclerotial formation of M. phaseolina isolates which isolated from sesame and sunflower plants. The highest effect on the reduction of M. phaseolina linar growth and number of sclerotial formation was recorded with CaSO4 at 400 ppm. Using both of soaking and sprayer with CaSO4 whether separately or together gave a significant decrease of charcoal rot and incidence of survival plants compared with control, while the effect of CaSO4 on reducing of diseases incidence increased with increasing of their concentration under greenhouse and field conditions. Use of CaSO4 at 800 ppm as soaking and sprayer method together recorded the highest effect on decreasing of charcoal rot as well as increasing total seed yield of sesame and sunflower plants during the two growing seasons 2008 and 2009.