Is it Mesophyll Cell Collapse?
If you suspect a plant is suffering from mesophyll cell collapse, a quick but careful inspection can help to confirm or rule out this diagnosis. Check not only the affected plant, but the entire collection, especially the surrounding plants. — Thrips can cause damage to orchid plants that is similar in appearance to mesophyll cell collapse. Inspect affected plants carefully for thrips or their eggs, which are normally laid just under the upper epidermis of the leaf. — Rule out the possibility of chemical damage by checking each chemical used for dosage and compatibility. Make certain that the chemicals used are labeled as safe for orchids, and that the recommended dosage has not been exceeded. — Although it may appear similar at first glance, mesophyll cell collapse can be distinguished from virus problems in that it occurs mainly on developing leaves and is usually evident on only one or two of the new leaves. The next leaf produced should appear normal. — Eliminate sudden changes
