POTATO VINE PREMATURE DECLINE IN NORTH CAROLINA: Causes and Management Marc A. Cubeta, Extension Plant Pathologist Nancy G. Creamer, Extension Horticulturist Carl R. Crozier, Extension Soil Scientist David Monks, Extension Horticulturist/Weed Scientist Kenneth A. Sorensen, Extension Entomologist

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Vegetable Disease Information Note No. 24
Department of Plant Pathology
North Carolina State University

For many years growers, county extension agents and consultants in eastern North Carolina and elsewhere have noticed that potato vines often die prematurely. The degree of potato vine premature decline varies among fields, years, and cultivars. Potato vine premature decline occurs in many areas in the United States where potatoes are grown, and has recently received considerable attention in books, magazines, newsletters and scientific journals. There are numerous federal and state research projects directed towards this problem. The problem has been referred to as "Potato Early Dying", "Potato Premature Death", "Potato Root Rot", "Potato Wilt", "Drought Injury", etc. In North Carolina many causes are associated with potato vine premature decline, including the Potato Early Dying complex, caused by the lesion nematode (Pratylenchus penetrans) and Verticillium fungi (Verticillium dahliae and V. albo-atrum), air pollution, insect damage, fertilizer salt damage, shallow hard pans and soilborne bacterial and fungal pathogens.

Effective management of potato vine premature decline relies largely on accuarate and proper diagnosis of the specific cause. However, in several instances, the combination of two or more causes may result in especially severe decline and death of vines (e.g. lesion nematode and Verticillium fungus; European corn borer and the black leg bacterium, etc.). Often the presence of one or more conditions may mask other problems. For example verticillium wilt and other diseases are often masked by high fertility, poor drainage, shallow hard pans and low soil pH (< 5.0). The purpose of this note is to provide county agents, consultants and growers involved with potato production in North Carolina with information about the many causes of potato vine premature decline and strategies for managing each cause. Usually several strategies are needed for managing potato vine decline. The causes and strategies for managing potato vine decline in eastern North Carolina are summarized in the table below.

Causes	Occurrence*	Crop rotation	Land selection	Land preparation	Assay seed and soil	Purchase certified seed	Plant resistant cultivars
Air pollution	5%	No	No	No	No	No	Yes
Bacterial wilt	<1%	Maybe	Yes	No	No	Yes	No
Black dot root rot	<1%	Yes	Yes	Maybe	Yes	Yes	No
Black leg	6%	Maybe	No	Yes	Yes	Yes	Maybe
Colorado potato beetle	4%	Yes	Yes	No	Yes	No	No
Drought	3%	No	Yes	Yes	No	No	No
European corn borer	10%	No	No	No	Maybe	No	No
Fusarium wilt	2%	Yes	Yes	No	No	Yes	Maybe
Herbicide damage	2%	Maybe	Yes	No	Yes	No	No
High, soil soluble salts	7%	No	Yes	Yes	Yes	No	No
Lesion and root-knot nematodes	1%	Maybe	Yes	No	Yes	No	No
Low soil pH (<5.0)	3%	No	Yes	Yes	Yes	No	No
Nutrition	3%	No	Yes	No	Yes	No	No
Poor drainage	3%	No	Yes	Yes	No	No	No
Pythium root rot	<1	Maybe	Yes	Yes	No	No	No
Rhizoctonia stem canker	5	Yes	Yes	Yes	Yes	Yes	No
Seedpiece decay	15	No	Yes	Yes	Yes	Yes	No
Shallow hardpan	10	No	Yes	Yes	No	No	No
Southern stem rot	10	No	Yes	Yes	Maybe	No	No
Verticillium wilt	2	Maybe	Yes	No	Yes	Yes	Yes
Viruses (leafroll,PVY)	1	No	No	No	Yes	Yes	Maybe

* Occurrence was determined by examining Plant Disease and Insect Clinic records from 1969 to 1996.
Yes = usually an effective management practice for reducing potato vine premature decline,
No = usually not an effective management practice for reducing potato vine premature decline,
Maybe = may or may not be an effective management practice for reducing potato vine premature vine decline.

Crop rotation means that potatoes were not grown in the same field for at least 2-3 years.

Land selection includes: assessing fields for previous drainage, disease, insect, nutrient and weed problems.

Land preparation includes: ditching, leveling and primary tillage operations.

Assaying potato seed and soil includes: carefully examining potato seedpieces for diseases and insects. Soil assays for nematodes and herbicide residues can also be performed.

Purchase certified seed from a reliable source and get to know your seed growers. Also evaluate seed quality, warm seed prior to cutting, and treat cut, seedpieces with a drying agent or fungicide prior to planting, if needed.

Planting a resistant cultivar means using a potato variety that has resistance to a specific cause of potato premature vine decline. Certain resistant varieties may have undesirable horticultural traits.

This page (http://www.ces.ncsu.edu/plymouth/potatoVine.html) was created by Marc A. Cubeta, Ph.D. Extension Plant Pathologist and Bruce A. Emmons, Area Specialized Agent, Information Management. The authors would like to acknowledge Frank Winslow, Washington County Extension Agent; Tom Campbell, Pasquotank County Extension Agent; Drs. Tom Melton and Jack Bailey, Department of Plant Pathology, North Carolina State University, Raleigh, NC for reviewing this publication and their many valuable comments and suggestions.

Date Created 10/03/96.
Last revised on 08/09/01.