Spraying weeds

I've been spraying weeds for a while now.  Yesterday I went back over the area I had sprayed in the north pasture so far to catch the weeds I missed and to catch the newer Canadian Thistle weeds that popped up.   I estimate I had to respray 10% of the weeds.  It was nice to be able to cover large areas on a tank of herbicide.   I am now back to smaller areas per tank.  I have lots left to spray.

I am wearing yellow tinted sunglasses while I spray.  Partly because of the sun, partly because the glasses protect my eyes from potentially drifting spray, and partly because the glasses makes the difference between the dead and living knapweed plants stand out.

Here are views with and without the sunglasses.  The "yellow" photo doesn't really capture what I see using the sunglasses as the dead plants look more reddish than what appears in the photo.