Hello. The nature of the deterioration cannot be accurately determined from the attached photos alone, but these stains may be caused by the action of pathogens (possibly a bacteriosis, but the exact diagnosis of the disease requires laboratory analysis).
In this case, it is recommended to carry out 2 treatments at an interval of 7-10 days with a fungicide such as , 20 g/10 L water, applied by foliar spraying. It is important to prepare a volume of solution corresponding to a single treatment (respecting the mentioned dosage), because the already prepared mixture does not have a shelf life longer than 24 hours.
10-12 days after the end of the treatments, in order to support the regeneration of the plants after the disease, you can consider using a special fertilizer that stimulates the healthy growth of the plants after a period of stress, such as .
Subsequently, it is recommended to follow the specific environmental and care requirements as described in our article: Orchid, plant care and growing guide. During the growing season, a fertilizer that is specially formulated for the nutritional requirements of this species, such as , can be administered when watering, as recommended in the product description.
In view of the aspects mentioned, i.e. the current condition of the orchids, it is not possible to say exactly how they will develop in the future.