How to Manage Pests
UC Pest Management Guidelines
Bacterial Soft Rot
Pathogen: Pectobacterium carotovorum ssp. carotovorum
(Reviewed 1/09, updated 9/12)
In this Guideline:
SYMPTOMS AND SIGNS
Bacterial soft rot appears as a soft, watery, and slimy decay of the taproot. The decay rapidly consumes the core of the carrot, often leaving the epidermis intact. A foul odor may be associated with soft rot. Aboveground symptoms include a general yellowing, wilting, and collapse of the foliage.
COMMENTS ON THE DISEASE
Pectobacterium carotovora is a common soilborne bacterium that attacks a wide range of fruits and vegetables. The bacterium enters carrots through various kinds of wounds. In the field, soft rot is most often associated with warm temperatures and standing water resulting from poor drainage, low areas, or leaky irrigation pipes. Carrots are most susceptible to infection when roots are mature and temperatures are warm.
In the field, maintain good drainage and avoid practices that could wound roots. Avoid prolonged irrigation of mature carrots during warm months of the year. In the packinghouse, handle carrots carefully to avoid bruising and store them under cool conditions. Chlorine (Decco 240 and Seachlor 100) added to the wash water helps to eliminate the soft rot bacteria from carrot surfaces.
UC IPM Pest Management Guidelines:
J. Nunez, UC Cooperative Extension, Kern County
Acknowledgment for contributions to Diseases:B. W. Falk, Plant Pathology, UC Davis
F. F. Laemmlen, UC Cooperative Extension, Santa Barbara County