Damping-off in Flower and Vegetable Seedlings
Ornamental Disease Note No. 14
Ronald K. Jones, Plant Pathologist (retired)
Charles W. Averre, Plant Pathologist (retired)
Damping-off is a common disease of seedlings in North Carolina. It causes extensive losses to growers through death of seedlings or production of low-quality plants that perform poorly in the field. The disease can be avoided and controlled by practicing effective preplant control measures.
True damping-off may be confused with plant injury caused by excessive fertilization, high soluble salts, drowning in wet soil, desiccation in dry soil, and death of seedlings from excessive heat, cold, fuel fumes, or chemical injury. This type injury often damages the leaves and upper stem before the roots are affected.
Once damping-off has started in a bed or flat, its spread may be reduced by providing drier conditions for better seedling growth. This can be done by increasing greenhouse temperature, increasing air circulation and ventilation, reducing the frequency of watering, providing better water drainage by ditching inside and outside the plant bed structure or greenhouse, and by increasing the amount of light by removing dirty covers, overhanging branches, removing shading materials, etc.
If the above preventive control measures fail, several fungicides are available that may be effective if applied as a drench or heavy spray as soon as the first symptoms of damping-off are observed. Growing conditions should be improved and flats or areas of bed with damping-off should be carefully removed from the growing area. Rapid identification of the causal fungus should be obtained so that proper chemicals can be applied (see county agent for diagnosis). Several applications of the fungicide may be necessary, If the specific fungus causing damping-off is not known, one broad spectrum fungicide (captan or ferbam), two specific fungicides (benomyl plus, etridiazole or metalaxyl) or a prepared combination of fungicides (etridiazole + thiophanate methyl) should be used. Check the current North Carolina Agricultural Chemicals Manual and the label carefully to be sure of the proper fungicide and rate to be used on a particular crop.
used to control damping-off are listed below along with general rates
(follow specific crop limitations and rates on the manufacturer's label):
*B.S. = (broad spectrum fungicide); R = (active against Rhizoctonia, Sclerotina, Fusarium, Botrytis); P = (active against Phytophthora and Pythium)
All of these fungicides can cause some stunting and yellowing of young seedlings. Do not use fungicides unless damping-off becomes or has been a problem. Wait as long as possible before using a fungicide as younger seedlings are more susceptible to fungicide injury than older seedlings.
For assistance with a specific problem, contact your local North Carolina Cooperative Extension Service
for the use of chemicals are included in this publication as a convenience
to the reader. The use of brand names and any mention or listing of commercial
products or services in this publication does not imply endorsement by
the North Carolina Cooperative Extension Service nor discrimination against
similar products or services not mentioned. Individuals who use chemicals
are responsible for ensuring that the intended use complies with current
regulations and conforms to the product label. Be sure to obtain current
information about usage and examine a current product label before applying
any chemical. For assistance, contact your county North Carolina Cooperative
Extension Service agent. 10/90/1000
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.
Reformatted Dec. 2000 by A.V. Lemay