Sunflower
Downy mildew Cottony fungus on underside of leaves. Dwarfing,
Plasmopara halstedi contrasting discoloration of yellow-green and green.
Blackening and sometimes swelling at base of stem.
Disease most severe when rain occurs before and after
emergence.
Powdery mildew Cottony fungus on green leaves late in summer - not largely
Erysiphe cichoracearum damaging.
Leaf spot Dead blotches on flower leaves before heading. Has not
Septoria helianthi caused appreciable loss.
Verticillium wilt Before heading, dead areas along leaf veins, bordered by
Sclerotinia sclerotiorum light yellow-green margins. Decayed vascular tissue in
cross-section of stem.
Rust Rust colored pustules on leaves, latter black specks on
annaabi.ee 
