Do you find the Auto Backup feature of Google+
Photos frustrating? A lot of people do, and it is very
easy to turn it off. Basically, there are a handful of
ways to stop your photos from being recorded /
saved on the Auto backup feature and I will outline a
few of them here.
Disabling Content From Picassa
From your android smartphone:
1. Tap on
Gallery
2. Click on the Menu button to show a list of options
3. Choose
Content to Display
4. Uncheck the Content from Picassa option.
5. Visit Google+ from your PC to remove the photos
from your Google plus account. With "content from
picassa" disabled in your gallery, your new photos
will not be auto backed up and you should no longer
see the photos.
Clear Backup Auto Data From Google Plus
1. Visit Google+ from your computer
2. Delete all the photos you do not want.
3. Navigate to
Settings.
4. Choose Apps from the settings menu.
5. Near the top of the page where there are sections
for 'Downloaded', 'Running', 'All', Choose
All (you
may have to swipe left to see it).
6. Under the menu items for All, choose
Gallery, then
choose Force stop, then choose Clear data.
That's it. If you are having trouble getting rid of the
backup photo album from google plus gallery, leave a
reply below and I'll look into it.

More Here: http://9jabaze.forumotion.com/t9-how-to-delete-auto-backup-album-from-google-plus-gallery