Problem with common sunflowers and Giant Mexican Sunflowers
I'm having similar leaf problems with both common sunflowers and Giant Mexican Sunflowers. Leaves are turning yellow in patches, then those same areas become brown and shriveled.
Any idea what could be causing this?
Helianthus annuus - Problem became noticable about three weeks ago and has since progressed.
Tithonia diversifolia - Problem became noticable about two weeks ago and has rapidly progressed.
Thanks for any help!