Never seen this before

[Bondad]

I have these white patches on underside of my ficus. I'm very familiar with white fly and similar pests. This is different, it's almost like when salt evaporates off a surface. You can't remove the white patches like you can with white fly or thrips. Any info or ID appreciated

 

[Shibui]

Looks very like residue from water evaporating. Calcium is a common impurity in many water sources and I see many posts from USA about high pH or high calcium in municipal water affecting plants in various ways.
Water here has calcium so I get similar white calcium deposits on the leaves in warmer weather, especially in the misting bed for cuttings.
Check the water report for your water supply to see what calcium levels or other minerals are present.

 

[Potawatomi13]

Tried wash off with damp cloth?

 

[Bondad]

Looks very like residue from water evaporating. Calcium is a common impurity in many water sources and I see many posts from USA about high pH or high calcium in municipal water affecting plants in various ways.
Water here has calcium so I get similar white calcium deposits on the leaves in warmer weather, especially in the misting bed for cuttings.
Check the water report for your water supply to see what calcium levels or other minerals are present.

YES, Thank you so much. Wasn't even thinking in that direction. Should be able to make watering source adjustments to correct

 

[Huggz13]

Looks like hard water to me too - calcium and magnesium usually the culprit.