and life cycle—Downy mildew
Peronospora parasitica requires cool, moist weather for infection and disease development to take
place. The pathogen survives between crops on weed hosts or as resilient oospores in crop residue. Spores
are airborne. This disease is most serious on young seedlings; if cotyledons and the first true leaves
are severely infected, the young plant may die.
of downy mildew