Soil texture and quality of irrigation water as factors affecting the infection rates of peanut seedlings with Rhizoctonia solani were studied. Aspergillus niger, Fusarium spp., Rhizoctonia solani and Macrophomina phaseolina were prevalent over the collected rotted samples of peanut roots and fruits in frequencies of (12.0-27.2%). Results indicated that the highest rate of infection (62.67%) occurred in sandy soil, while sandy clay soil gave the lowest rate (53.33%). The highest infection rate (70.67%) was obtained when irrigation was carried out using ground water. However, irrigation with Nile River gave the least infection rate (46.67%). Laboratory experiment using Ca++ and Na+ ions confirmed the results obtained from the pot experiment irrigated with agricultural waste water which is considered reach in Ca++ and Na+ ions.