Biological control of Golovinomyces cichoracearum, the causal pathogen of sunflower powdery mildew

Abstract Background Powdery mildew was found in most of the sunflower fields Egypt, causing severe yellowing blade, petiole, stem and calyx, as well a considerable defoliation during summer season 2018. Out fungal mycelium from infected leaves, collected four Egyptian Governorates (Kafr El-Sheikh, Gharbia, Giza El-Beheira), five isolates powdery pathogen were obtained identified using morphological molecular identification methods. Results In 2019 2020 seasons, biocontrol agents ( Bacillus subtilis , B. pumilus Trichoderma harzianum T. virid e koningii ) used to control disease on plants under field conditions compared with fungicide (Vectra 10% SC). Treatments significantly effective for controlling relative control. The best treatment reducing parameters (final severity (FDS%), area progress curve (AUDPC) efficacy) than koningii. Foliar application all tested treatments improved plant height, head diameters seed yield relation untreated (control). components (FDS%, AUDPC extracted described approximately 95.251% pooled data seasons 2020. such data, principal (PC1, PC2 PC3) parameters, development recorded 76.305, 86.635 96.265% total variance, respectively. Conclusion A biological agent, can be suggested based experimental findings.