Dr. Phyto

sunflower

Helianthus annuus

Diseases & pests on this plant

• sunflower downy mildewPlasmopara halstedii

  Stunted seedlings with chlorotic upper leaves + white downy growth on undersides, dwarfed plants (basal infection) producing no head or sterile head, systemic infection causes stunting + leaf yellowing, secondary leaf spots in mid-season, fluffy white sporulation on leaf undersides in humid mornings.

• sclerotinia stem rotSclerotinia sclerotiorum

  White cottony growth on stems at flowering height, stems split open to show black sclerotia (1–5 mm) embedded in pith, premature ripening of affected plants.

• Phomopsis stem canker of sunflowerPhomopsis helianthi

  Brown sunken lesions at leaf attachment points on stems (the diagnostic location), lesions expand into elongate stem cankers, severe stem lodging at flowering or seed-fill, head abortion + sunflower seed yield loss 30-80%, secondary fungal saprobes colonize cankers late season.

• grey mould (Botrytis)Botrytis cinerea

  Fuzzy grey mould on leaves and stems.