Southern Bacterial Wilt on Marigolds
Ornamental Disease Information Note 9
R.K. Jones, Plant Pathologist (retired)
D.M. Benson, Plant Pathologist




[Distribution and Host Range] [Symptoms] [Control] [Back to Ornamental Disease Notes] [Other Resources]

Distribution and Host Range

Southern bacterial wilt, caused by Pseudomonas solanacearum, is a widespread and destructive disease of numerous crops in the warm climates of the world. It is a major disease of tobacco, tomato, potato, dahlia, geranium, hollyhock, hydrangea, marigold, nasturtium, zinnia and others. Bacterial wilt is the most frequent disease problem of marigolds in North Carolina landscapes.

Symptoms

Infected plants may become stunted with foliage light green to chlorotic (yellow) or grey green in color. The upper foliage may wilt slightly in the early stages of the disease but the plant rapidly wilts completely. Diseased plants often die within 7-14 days after the first symptoms are observed.
Control

Southern bacterial wilt is a difficult disease to control. There are no chemicals that provide effective control before or after planting.

The only control is to avoid susceptible plants or to grow resistant cultivars. The following marigold cultivars are resistant to bacterial wilt: Cupid; Irish Lace; Papaya Crush; Pineapple Crush; Pumpkin Crush; Rusty Red; Sparky; Sparky Mix; Bonanza Yellow; Choice Mix; Copper Canyou; Cupid Mix; Fort Knox; Golden Harmony; Goldie; Gypsy Dancer; Naughty Marietta; Orange Lady; Senator Dirksen; and Tangerine Gem. If it is necessary to grow a susceptible cultivar in an area where the disease has been a problem in the past, plant the susceptible cultivar in another part of the area or plant them in new soil or a soil-less media in planter boxes.

Other Resources

Plant Disease Information Notes
Horticulture Information Leaflets Home Page
HIL-550 Field Grown Cut Flower Production
HIL-552 (PDF file) Selection and Use of Stress-Tolerant Bedding Plants for the Landscape
HIL-555 (PDF file) Installation and Maintenance of Landscape Bedding Plants
HIL-644 Weed Control in Flower Beds
North Carolina Insect Notes
North Carolina Agricultural Chemicals Manual
NCSU Cooperative Extension Service

For assistance with a specific problem, contact your local North Carolina Cooperative Extension Service personnel.

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Published by the North Carolina Cooperative Extension Service
Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.

Last update to information: March 1996
Last checked by author: May 1996
Web page last updated on Dec. 2000 by A.V. Lemay