Root rot and wilt are considering the most important diseases, causing serious yield losses of rosemary plant. The aim of this work was to investigate the occurrence and distribution of root rot and wilt diseases of R. officinalis and identification of their causal pathogens. Also, develop control safe means to management these diseases.
Root rot and wilt rosemary plants symptoms were collected from Qalubyia and Giza Governorates during season 2017. The pathogenicity tests of the isolated fungi, i.e. (Fusarium oxysporum, F. solani, Macrophomina phaseolina, Pythium debaryanum, Rhizoctonia solani and Sclerotinia sclerotiorum) revealed the ability of these fungi to cause infection. Application of some safe alternatives fungicide and fertilizers, i.e. potassium silicate, bioproduct (Plant Guard) and NPK fertilizer compared with systemic fungicide, Carbendazim 50% WP, against the isolated fungi were performed in the greenhouse.
All the tested treatments significantly reduced disease incidence under greenhouse conditions. While, the treatment (NPK + Potassium silicate + Plant Guard) was more efficient in reducing infection of root rot and wilt diseases in the field during 2018 & 2019 and superiority increasing of growth characteristics. Gas chromatographic analysis of rosemary essential oil showed that, Camphor was found as a major component (33.18%), followed by Eucalyptol (1,8-Cineole) with (NPK + Potassium silicate + Plant Guard) treatment. Also, the total phenols and flavonoids content as antioxidants improved with the same treatment in comparison with control.