Maybe it's spider mite, you can use neem oil , H2O2 or alcohol.
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Can anyone help me to identify what is causing these white patches? I don't see any insects on the leaves and the plant looks quite healthy apart from these but it doesn't look very nice...
Maybe it's spider mite, you can use neem oil , H2O2 or alcohol.
Concur with Dr.Zainal. Looks like spider mites.
Pardon my ignorance, but could it also be water-spotting if this person mists the leaves semi-regularly, ESPECIALLY SINCE THEY COMMENTED THAT THEY ALREADY LOOKED FOR INSECT ACTIVITY? I'm one of those people that tends to think positive and accepts what the person tells me as being the truth. I am assuming that they know what spider mites are and ruling that out, the thing that comes to mind is water-spotting. The other reason I say that is, I have some that are more sensitive to being misted. Some of my plants get that very quickly while others never do. Is this a viable possibility?
you could try to remove the spots by mixing 1 part full fat milk:10 parts of water and wipe & clean it with this solution. if it vanishes, it is salt residue in water. You could also observe with a magnifying glass. let us know how it goes.
Will do, thanks for the suggestions!
Since the 'patches' occur on the surface of the leaves I don't think that they are spider mites as these tend to occur on the under sides of leaves. Most probably water spots/ chemical or fertilizer residue.
Thanks again everyone for the suggestions - I wouldn't have thought of water spotting as a possibility... This morning, I tried the diluted milk method and here are photos of the plants after...
It seems like it's not very different so I'm not sure it's water spotting or residue... Also, of all the orchids I have which are sprayed with water, this is the only one which has this condition...
I've ordered some neem oil to give that a try and will let you know if that helps. I do also grow herbs on the balcony and some of them have had problems with thrips and spider mites so it could well be that... If it is an insect attack, I guess I will only know if the neem oil works after the new growth appears as the leaves which have currently been damaged will presumably not be restored - is that right?
Appreciate everyone's efforts to help me solve this! Keep those suggestions/thoughts etc. coming!
I think it is mite problem as well. You probably should use miticide for mites.
The damage does look rather spider mit-ish. If you use neem oil, keep in mine to keep your plant out of sunlight until the oil is quite dry, if the oil is wet the droplets can magnify the light and cause damage to your leaves. Spider mites are pretty hard to see. If I see the pictures right, it looks like the damage is on the bottom of the leaf and shows on the top too. This is pretty indicative of spider mites. My vision isn't too great, I don't bother to look for the mites, when I see damage I just treat for them. You are right the old leaves won't so much recover, but the damage will stop and the new ones will be healthy. So far I haven't had spider mites on my orchids, but my neighbor had them ruin his arborvitae in his yard.