Boxwood is dying

[Tom T]

Hello all.
I just joined this forum today. I bought my house 2 years ago and came with mature landscape. I live in Las Vegas, NV. The first year we moved in and I did not know how to set the irrigation system. It watered the landscape very heavily and the plants and boxwood shrubs pretty healthy. Everything uses the drip system and now it set to about 30-40 mins every other day at 5pm.
This summer got pretty hot. Some of the boxwood shrubs is dying. I am new at this landscape care and tried decrease and increase the watering but see no improvement. So I turn to this forums for advice. I just don't want to lose all my shrubs.
I also wondering if anyone can tell me what kind of boxwood shrubs these are.
Here are the pictures:

 

[alp]

You have to burn the dead leaves and take cuttings from the healthy stems as they root very readily. Once you have a few rooted cuttings, you will wonder why they are so dear in the first place.

 

[Robert Cummings]

I think the reason your bosworth is dying is possibly an aphid infection, these little critters suck the sap out of plants making them look tired and lifeless, you could try an insecticide spray..

 

[alp]

Or it could be fungal, have a look here

https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/yellow-or-brown-boxwoods.htm