My rhododendron is sick

Hi, does anyone know what is wrong with the rhododendron tree? The white spots are everywhere, and the leaves are turning yellow. Is that fungus? (pictures attached)

 

Harmless lichens

 

Besides the harmless lichens @Ron B notes, it is common for the oldest leaves of rhododendrons to yellow and fall off at this time of year.

You have no apparent reason to worry about your shrub.

 

@Summer_tequila good morning and welcome to the forum. Firstly I agree with both comments already submitted by Ron and Margot. But can I add just one thing regarding the yellowing of the leaves, yes they will drop the old ones every year, but I add some diluted sequested iron after flowering has finished each year together with a granular feed for acid loving plants and this does help mine. I have very little leaf loss.
I also saw some Ivy approaching your Rhodedenron, IMO it would be a good idea to remove this.

 

I agree with @Acerholic that the addition of iron or fertilizer will help those rhododendrons whose leaves are yellowing prematurely due to chlorosis but it is important to know that rhodos, like all 'evergreens' do lose their older leaves eventually and there's nothing you can do to prevent that. Depending on the species and variety, some will hold their leaves for as many as 4 years while others lose even 2-year-old leaves. This usually doesn't happen until new growth is established.