WSU Extension

Hortsense

Herbicide Damage : Dichlobenil (Casoron)
(revision date: 5/1/2013)


Biology
Dichlobenil is a soil-applied herbicide which inhibits root development and prevents germination and establishment of weed seedlings. While dichlobenil is not translocated in the plant, symptoms resulting from inhibited root growth may appear on aboveground portions of the plant. The primary aboveground symptom of damage is chlorosis. On broad-leaved plants this can be tip, marginal, or interveinal yellowing, or can appear as overall yellowing of the leaf. On conifers, excessive dichlobenil applications can cause tip chlorosis tending toward tip necrosis. Symptoms usually appear on the new growth. The damage may occur on those leaves and leaf parts that orient toward the afternoon sun. Dichlobenil damage closely resembles triazine/simazine damage. This herbicide is persistent in the soil and decomposes slowly.
Management Options

Non-Chemical Management
  • Do not overapply or apply dichlobenil near sensitive plants.
  • Read pesticide labels carefully prior to purchase and application.
Select non-chemical management options as your first choice!

Chemical Management

Carefully read all label instructions prior to using products containing dichlobenil.

Images
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Caption: Pine casoron damage
Photo by: R. Maleike
Caption: Rhododendron casoron damage
Photo by: R. Maleike
Caption: Turf casoron damage
Photo by: R. Maleike
Caption: European hornbeam casoron damage
Photo by: R. Maleike
Caption: Land firethorn casoron damage
Photo by: R. Maleike
Caption: Kwanzan cherry casoron damage
Photo by: R. Maleike