Blotchy leaves on butternut squash

[glaw5]

Hi, just a quick question about my butternut squash plant.

I've just got the one large fruit on it as others have appeard to have rotted/died off when they were very small. I've regularly removed these but the leaves on the plant look blotchy and not very full of colour.

Is this the butternut squash almost robbing the rest of the plant of energy? Or is there something I can do to improve the situation? The butternut squash itself looks healthy from what I can see.

Thanks for any help.