What's wrong with my sunflowers?

[C00KiE46]

Starting from the bottom the leaves turn yellow and shrivel off. Why could this be happening? Do you think it could be due to insects eating the leaves? Also what could those dried brown dots be from?
[img]https://i203.photobucket.com/albums/aa241/M0MMiE_album/IMG_3579.jpg[/img]
[img]https://i203.photobucket.com/albums/aa241/M0MMiE_album/IMG_3578.jpg[/img]

[nes]

Look on the underside of the leaves for little bugs with lots of ants running around - I'd be you have aphids.

[C00KiE46]

I looked up aphids cause I was clueless on what those were and you were right. I have them, now I need to figure out on how to get rid of them.

[C00KiE46]

I looked up aphids cause I was clueless on what those were and you were right. I have them, now I need to figure out on how to get rid of them.