Hello. The symptoms are similar to those caused by powdery mildew, and the brown spots on the leaves seem to be caused by a leaf spot disease (most likely bacterial in nature). In this case, it is recommended to remove the affected leaves (they will not be left on the ground) and carry out a first treatment with a fungicide such as , in a dose of 20 g/10 L water, and after 7 days, you can alternate with , in a dose of 5 ml/10 L water. Treatments are applied by foliar spraying in the early morning when temperatures are not very high.
It is advisable to respect the preharvest interval between the last treatment and the harvest time of the vegetables mentioned on the product label.
At the same time, in order to stimulate plant growth and revitalization, you can consider using a fertilizer such as , 500 ml, applied by watering the roots, according to the recommendations on the label.
In the future, for disease and pest control, you may consider preventive treatments during the growing season, depending on the phenotype.