The effect of seven substances, Copper,  CuO, ZnO, AlO NPs (8 mg L−1), CuO, ZnO, AlO (8 mg L−1)  and chitosan   was evaluated  under  both  greenhouse   and field conditions during  two growing seasons (2017/2018  and  2018/2019) to control powdery mildew disease caused by  Erysiphe cichoracearum on marigold (Calendula officinalis). Results have shown that all the treatments tested had decreased disease severity compared to the non-treated control.  In this respect, chitosan showed the best effect in decreasing disease severity followed by ZnO NPs. Meanwhile, CuO gave the lowest effect in this respect. The decrease in disease severity of powdery mildew was positively expressed by an increase in crop parameters, i.e. numbers of inflorescence weight, fresh and dry weights of plants, plant height, number of  branches and increased  chlorophyll ( a and b) and carotenoids.