Rust Puccinia spp. Orange to brown elliptical lesions on leaves and stems. With heavy infections, reduced leaf area will result in lower seed yield. Seed decay and seedling disease Pythium, Fusarium and other fungi 1. Poor stand establishment.
Seed fail to germinate or seed germinate and the roots decay.
Dying small plants, wrinkled and twisted leaves of young plants, reduced and irregular heads, and presence of cockles in the seed head. Destroy plant debris. Use clean seed. Other nematodes 1. Above-ground symptoms depend on the level of infestation.