Abstract
Powdery mildew caused by the fungus Erysiphe cichoracearum DC. or Podosphaera fusca (Fr.) S. Blumer is a common disease on gerbera daisies (Gerbera jamesonii Bolus ex. Hook f.) grown in Florida. This disease affects all parts of the plant and reduced plant quality is the main component of economic loss. The effect of calcium silicate, potassium silicate, and the biofungicide products Actigard (acibenzolar-S-methyl), K-phite (phosphorous acid), Milstop (potassium bicarbonate), Tricon (boron, orange oil and organic surfactants), Cease (Bacillus subtilis) and AgSil (potassium silicate) were evaluated in highly susceptible (‘Snow White’ and ‘Orange’) and moderately susceptible (‘Hot Pink’ and ‘Fuchsia’) gerbera cultivars. Results suggested that neither calcium silicate nor potassium silicate were effective in suppressing powdery mildew in gerbera daisy. The biofungicides products Actigard, Agsil, Cease, K-phite, Milstop and Tricon, suppressed powdery mildew of gerbera daisy compared with untreated plants; however, these products were not as effective as the fungicide program of Heritage alternated with Eagle. Among the biofungicide products tested K-phite, Millstop and Tricon were the most effective in reducing disease severity. Thus, biofungicide products may be used as an alternative to reduce the use of fungicides for suppressing powdery mildew of gerbera daisy.
