Hello. From the information given and the attached pictures, most likely the symptoms mentioned (mold in the potting soil, affected leaves) were caused by high/persistent humidity in the potting soil. In our shop, we do not have a specific product to control mold in the pot, but to avoid its development it is advisable to water the plant less often, letting the substrate dry slightly between waterings, avoiding water stagnation in the tray. You can also consider replacing the surface potting soil with a fresh one () and placing the pot in a drier, airy, and bright place. Browned leaves can be removed as they will not recover.
As a preventive measure, to limit the appearance of pathogens that develop in conditions of high humidity in the soil, you can also consider 1-2 treatments, at 10 days intervals, with a biological fungicide such as , by watering, in a dose of 10 g/ 10 L water, according to the instructions in the product description. It is important to prepare a volume of solution corresponding to a single treatment (respecting the mentioned dosage) because the mixture already prepared does not have a valability longer than 24 hours.
Afterward, 10-12 days after the fungicide treatments have been finished, you can consider using an organic fertilizer in the form of tablets, which provides the plants with the necessary nutrients for growth and development: .
For more information on the specific care requirements of these species, please see our article: Strawberry, planting, growing and harvesting.