Effects of Foliar Sprays of Phosphates on Powdery Mildew Sphaerotheca pannosa of Roses

R. Reuveni, V. Agapov, M. Reuveni, M. Raviv

Research output: Contribution to journalArticlepeer-review


Powdery mildew on plants of a local clone of Rosa indica Major was significantly controlled by a single spray of 25 mM aqueous solutions of K2HPO4, KH2PO4 plus KOH, or NaHCO3, all plus Tween 20 (0.5 ml/l) or bupirimate (Nimrod) at 0.5 ml/l, which was applied 4 days before inoculation with conidial suspension of Sphaerotheca pannosa var. rosae. Disease incidence was reduced by 79, 71, 54 and 50%, as compared to controls on plants sprayed with KH2PO4 plus KOH, K2HPO4, NaHCO3 or bupirimate, respectively. Phosphates were suppressive and expressed by disappearance of 99% of the pustules and conidia, as early as 2 days after a single spray on mildewed foliage. This treatment was efficient for at least 9 days after the first application when large infected greenhouse‐grown plants were used. Re‐application of these salts on the same plants reduced the lesion area by about 90% from that recorded before the application. Phosphate and bicarbonate were more suppressive than the systemic fungicide bupirimate in the early period (up to 2 days). The suppresion effects of bicarbonate and bupirimate, however, were short‐term and not persistent, while the phosphate treatments remained significantly suppressive for up to 23 days, when the experiment was terminated. The inhibitory and suppressive effectiveness of phosphate salts is discussed in the light of their possible acceptance as ideal foliar fertilizers which should be considered for use in the field for disease control.

Original languageEnglish
Pages (from-to)331-337
Number of pages7
JournalJournal of Phytopathology
Issue number3
StatePublished - Nov 1994

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Agronomy and Crop Science
  • Plant Science


Dive into the research topics of 'Effects of Foliar Sprays of Phosphates on Powdery Mildew Sphaerotheca pannosa of Roses'. Together they form a unique fingerprint.

Cite this