MANAGEMENT OF SOYBEAN ROOT ROT DISEASES USING MICROWAVE THERMOTHERAPY, POTASSIUM SILICATE AND SODIUM BICARBONATE

Soybean root rot diseases were occurred wherever soybean cv. Giza 111 grown among different districts of Assiut and El-Minia Governorates, Egypt. Root rot incidence was varied with different districts and growing seasons. Disease incidence significantly higher in 2015 (10.71%) than 2014 (6.16%).  Assiut district recorded the highest district (12.35%) followed by Dermowas (8.65%). Six fungal species belong to five genera, namely Fusarium solani, F. oxysporum, Macrophomina phaseolina, Rhizoctonia solani, Alternaria sp., and Stemphylium sp. were frequently isolated from root rotted soybean samples. The highest frequency (33.5%) was record by F. solani followed by F. oxysporum (20%), R. solani (18.0%), M. phaseolina (17.0%), Alternaria sp. (6.0%) and Stemphylium (5.5%). Only the tested isolates of F. soalni, F. oxysporum, M. phaseolina and R. solani were pathogenic.
Microwave electric field radiation (MER), K. silicate (PS) and Na. bicarbonate (SB), were significantly reduced soybean root rot when seeds were treated before planting.  In addition, MER treated seeds for 6 sc exposure time and subsequently immersed in PS or SB solution, individually for 12 hr. before planting significantly reduced root rot severity more than single treatment. Since highest reduction was achieved when soybean seeds were MER treated followed by PS treatment, 45.97, 55.61, 60.00 and 62.09% reduction against infection with F. solani, R. solani, M. phaseolina and F. oxysporum, respectively