Vol. 115 (2002): Proceedings of the Florida State Horticultural Society
Vegetable

Use of kaolin clay for disease control in greenhouse cucumbers

Elizabeth M. Lamb
University of Florida
Erin N. Rosskopf
USDA ARS
Chip Koblegard
K and M of the Treasure Coast
front cover of vol 115, 2002

Published 2002-12-01

Keywords

  • cucumis sativus,
  • didymella bryoniae,
  • downy mildew,
  • gummy stem blight,
  • phosphite,
  • pseudoperonospora cubensis
  • ...More
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Abstract

Greenhouse vegetables have a high value in the marketplace and consequently consumers have a low tolerance for imperfections. Diseases can be a limiting factor in the high temperature and relative humidity environment of a greenhouse. Because greenhouse vegetables are a relatively small pesticide market, there are few chemical compounds labeled for use in greenhouse production. Foliar applications of clays, such as kaolin, have been suggested as a method of reducing fungal diseases by interfering with the ability of the fungus to penetrate the leaf surface. Foliar kaolin sprays and a phosphite foliar fertilizer (Ele-Max) were compared to current standard chemical sprays for control of downy mildew and gummy stem blight on European cucumbers in a commercial greenhouse. Alternative disease treatments were comparable to the conventional spray program in controlling disease. However, Ele-Max-treated plants had significantly lower yields than all other treatments.