How to Manage Pests

UC Pest Management Guidelines

| More pests | More crops | About guidelines |

Citrus

Exocortis

Pathogen: Exocortis viroid

(Reviewed 7/03, updated 7/03)

In this Guideline:

Symptoms
Comments on the disease
Management

SYMPTOMS
The characteristic symptom of exocortis is the shelling of susceptible rootstocks. The viroid kills the bark, which dries, cracks, and may lift in thin strips. Some droplets of gum often appear under the loose bark.

COMMENTS ON THE DISEASE
Exocortis is of minor importance in California today because strict regulations on budwood sources have kept new plantings largely free of this viroid disease. Exocortis is widespread in older plantings, but it is a mild disease that causes only moderate stunting and some loss of production. The viroid is easily spread on infected budwood and contaminated propagation tools.

Infected trees rarely die, but growth is retarded and productivity slowly declines. Among the commonly used rootstocks, trifoliate is most affected by exocortis.

MANAGEMENT
It is best to remove infected trees from the orchard because pruning clippers and saws can transmit exocortis unless thoroughly disinfected with hypoclorite (bleach); heat does not kill the viroid.

PUBLICATION

UC IPM Pest Management Guidelines: Citrus
UC ANR Publication 3441
Diseases
H. D. Ohr, Plant Pathology, UC Riverside
J. A. Menge, Plant Pathology, UC Riverside

Top of page

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See How to manage pests, or in the U.S., contact your local Cooperative Extension office for assistance. /PMG/r107100511.html revised: July 12, 2004. Contact webmaster.