Theme 48295 – Cherry/Dentist Ver 3.1.5

I am using the above Theme which has a pale blue background. Just within the blog pages I would like to remove the colour and have just white (no colour). Can I do this? And if so how? I thought I changed the background in some customise settings but nothing has changed. I don’t like the look of it when I insert a graphic image that mostly not transparent it looks ugly. My site is http://www.lifelonglearning.com.au — you will see what I mean with the colour but I only want to remove the background colour on the blog pages. Thank you.