This appears as irregular powdery
white spots on the upper surface of the lower leaves. Can be destructive in
dank weather and on older plants.
Best controlled by fungicides containing Pyrifenox. Cutting off old
lower leaves of sweet peas may help by improving air circulation, and reducing
the source of further infection.
Examples of Fungicides
(Myclobutanil - Neem Oil – Propiconazole - Thiophanate-methyl )