Assessment of the efficacy of mono-potassium phosphate in controlling powdery mildew (Oidium mangiferae) in mango inflorescences in relation to concentration and stage of inflorescence development.
Oosthuyse S. A.
Author Affiliation: HortReseorch SA, PO Box 3849, Tzaneen 0850, South Africa.
27 : 71-74
Abstract : Monopotassium phosphate [potassium dihydrogen phosphate] (MKP) has been found effective in suppressing powdery mildew in mango (caused by Oidium mangiferae) inflorescences. The efficacy of MKP against powdery mildew on mango (cultivars Tommy Atkins, Kent and Keitt) inflorescences was evaluated in Tzaneen, South Africa, during 2007 with respect to the stage at which MPK was applied (commencement of flowering or 80% flowering) and MKP concentration (1.0, 1.5 or 2% w/v). Folicur [tebuconazole] or Bayfidan [triadimenon] application at the commencement of flowering or 80% flowering stage was used as the control. MKP application at the commencement of anthesis was superior to MKP application at 80% flowering stage when symptoms were becoming apparent. MKP rates of 1.5 and 2.0% were equally effective, and almost as effective as Folicur or Benlate spraying. Fruit set and the degree of inflorescence colonization were negatively correlated. The results showed that MKP is effective against powdery mildew in mango inflorescences, particularly when applied at 1.5 or 2% with a surfactant during the commencement of anthesis.