The resistance of cucumber and squash to powdery mildew (Sphaerotheca fuliginea) was estimated based on conidia germination and mycelium formation on detached leaves kept on moist filter paper under high humidity. No direct relationship was found between oxidation-reduction potential (ORP), pH, and susceptibility. However, two susceptibility zones were identified: cotyledons with pH ~6 and ORP ~+50 mV, and older leaves with pH ≥7 and negative ORP. Similar results were found in squash tissues.
Benada J. (1974): The susceptibility and the resistance of the tissues of cucumber and squash to powdery mildew Sphaerotheca fuliginea in the dependence on oxidation reduction potencial and pH. – Česká Mykologie 28(1): 44–53.
