could it be fertilizer burn???

watering in hot sunshine???

is there a powder on the leaves.. as in powdery mildew???

ken

Thats a whole lot of mess, poor sunflower. I think you need a do over.

It looks like a lot things but the three that immediately come to mind are herbicide damage, potyvirus or some type of wilt.

I could see it being watering burn damage to the lower leaves but the new distorted growth and irregular chlorosis makes me think its a systemic problem.

What does the stem look like at the soil level?

http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm7735

Thank you for the replies.

The mini-sunflower is hanging in there, and I noticed the first yellow petals today. I think I'll still get a proper flower out of it.

I haven't used any herbicides. I sprayed if with a hot sauce, dish soap and water concoction to keep bugs away.

What is watering burn? I only water right at the base.

Last week or so I noticed it has a siamese twin coming out near it's base. Tiny, but it looks healthy.
The base of the stem is a little brown but looks sturdy.

There's one more sunflower growing to the right of it, and it is much bigger, and greener, but with some similar damage to the leaves.

Someone explain "watering burn " to me. In all my many years of watering plants with a hose, I have yet to witness such a phenomenon. I've gone out into the garden, nursery, or landscape beds thousands of times to water or cool the plants without one incident of burned foliage.

I know that you can't be referring to the myth that water droplets acts like tiny magnifying lenses, burning little bitty holes in the foliage.

I'll wager that the sunflowers have been infected with powdery mildew or even rust, both of which are common fungal diseases of sunflower. PM would get my first vote.

Ironically, one of the best preventative treatments for PM is.......(wait for it).......spraying the foliage with plain water!

one of the best preventative treatments for PM is.......(wait for it).......spraying the foliage with plain water!

==>>> key word.. preventative.. one you got it.. oh well ...

and if you try to prevent.. insure that the plant goes into dark.. dry ...

ken