Vol. 119 (2006): Proceedings of the Florida State Horticultural Society
Ornamental, Garden & Landscape

Efficacy of fungicides for control of a difficult fungus Erysiphe cichoracearum powdery mildew on gerbera daisy Gerbera jamesonii

Robert T. McMillan
University of Florida

Published 2006-12-01

Keywords

  • daisy disease,
  • fungicide efficacy

Abstract

Powdery mildew, caused by the fungus Erysiphe cichoracearum is a serious disease of Gerbera Daisy, Gerbera jamesonii. In 2005-06, five products, including conventional and a reduced risk biological fungicide, were trialed for efficacy against Erysiphe cichoracearum and Sphaerotheca fusca in a polyhouse at Kerry's Bromeliad Nursery. Six susceptible cultivars of Gerbera plants started from tissue cultured-liners were potted in 20.0 cm (8 inch) plastic pots. Natural infection was allowed to take place prior to the first application of the chemicals. Fungicides were applied on a 14 day schedule and replicated four times per treatment. Compass (trifloxystrobin) at 85 g (3 oz) per 380 L (100 gallon) of water, Heritage (azoxystrobin) at 85 g (3 oz) per 380 L (100 gallon) of water and Systhane (myclobutanil) at 142 g (5 oz) per 380 L (100 gallon) of water were significantly more effective in the control of powdery mildew than whole milk 480 ml (16 fl oz) per 380 L (100 gallon) of water.