NC State Extension Publications

Problem

Herbicide injury caused from dichlobenil.

Symptoms

  • Susceptible plants will not emerge if applied prior to weed emergence.
  • Susceptible plants will display general decline if applied after weed emergence.
  • In woody plants, dichlobenil may cause marginal chlorosis followed by necrosis.
  • Susceptible plants may be girdled at soil line, followed by wilting of the entire plant and then it turns brown. This is usually not uniform across the field.
Casoron overdose injury symptoms on apple.

Casoron overdose injury symptoms on apple.

W. A. Skroch  CC BY-NC-SA - 4.0

Casoron overdose injury symptoms on Kurume-type azalea.

Casoron overdose injury symptoms on Kurume-type azalea (non-treated on the right).

J. Derr, Virginia Tech  CC BY-NC-SA - 4.0

Plant Entry and Symptom Expression

Dichlobenil is a cellulose production inhibitor that works primarily on below-ground tissues but xylem transport to developing shoots may occur. This herbicide may be applied prior to or after weed emergence as it is absorbed through roots or young shoots. Dichlobenil is volatile and may be absorbed by any growing tissue.

Similar Problems

Dichlobenil injury may be confused with symptoms from:

  • Marginal chlorosis and necrosis caused by salt injury.
  • Triazine herbicides may cause similar marginal chlorosis.
  • General plant decline due to root damage caused by voles, root rot, severe nutritional deficiency (especially magnesium deficiency).

Herbicide Mode of Action Category

WSSA – 20
HRAC – L

Authors:

Professor of Weed Science, Extension Specialist & Department Extension Leader
Horticultural Science
Professor Emeritus
Cobleskill Univ.

Publication date: Dec. 14, 2015

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