Biological control of powdery mildew on chamomile plants

Abstract

Chamomile is considered one of the most medicinal and aromatic plants in Egypt and the world. Powdery mildew is among the most important diseases which attack chamomile in the different cultivation areas. Powdery mildew started to appear during November with very low disease severity. The peaks of disease incidence and severity were noticed during February and March. The fungal pathogen of this disease as was identified (Sphaerotheca fuliginea). Regarding bio control agents, the highest effect in controlling powdery mildew was recorded when Blight stop or T. hamatum was used. Indicate that the lowest percentages of powdery mildew incidence or severity were recorded when T. hamatum at concentration 20 ml/liter of water, or Blight stop at 10 ml ∕ liter of water was used. These low percentages in disease severities were correlated with the highest yield in plant inflorescences and obtained yield reached 0.833 and 0.845 tons/feddan when T. hamatum at concentration 20ml/liter of water, or Blight stop at recommended dose, respectively. Also, the highest plant height (cm), number of branches/plant, fresh and dry 100 inflorescences were obtained when T. hamatum was used, the highest essential oil content was recorded when T. hamatum or Blight stop were used. On the other hand, powdery mildew disease incidence led to increase free, conjugated and total phenols. Also, powdery mildew led to increase in reduced, non -reduced and total sugar contents. These results indicate the possibility of using T. hamatum or Blight stop as bio control agents against powdery mildew disease of Chamomile plants.