HPIPM:Potato Early Dying

Taxonomy

Domain	Eukarya
Kingdom	Fungi
Phylum	Ascomycota
Subphylum	Pezizomycotina
Class	Sordariomycetes
Subclass	Hypocreomycetidae
Order	Glomerellales
Family	Plectosphaerellaceae
Genus	Verticillium

Scientific Name

Verticillium alboatrum

Scientific Name Synonyms

Verticillium albo-atrum

Verticillium albo atrum

Common Name

Verticillium wilt

Author: Howard F. Schwartz and David H. Gent

Identification and Life Cycle

Early dying is a disease of potato caused by an interaction of soilborne fungi (Verticillium dahliae or V. albo-atrum) and various species of root-lesion nematodes (Pratylenchus spp.). Disease can be caused by Verticillium spp. alone when pathogen populations are high. Verticillium spp. that cause early dying have broad host ranges, but only certain strains are thought to cause disease on potato. The fungus infects roots and invades the vascular system, moving with water up the stem, and eventually invades the apical tissue. V. dahliae produces black, resting structures called microsclerotia that are capable of surviving in soil at least 10 years in the absence of a host. The pathogen survives between potato crops as microsclerotia or melanized hyphae and pathogenically on alternate hosts. The pathogen can be introduced into fields on contaminated seed pieces, in infested soil on equipment, and as windblown conidia.

Plant Response and Damage

Early blight symptoms initially appear as leaf yellowing, curling, and necrosis on one side of petioles. Younger leaves are generally the first to display symptoms, but as disease continues to develop symptoms progress up the plant. A slight brown discoloration of vascular tissues is apparent when stems are cut in cross-section, and may result in stem-end tuber discoloration in severe cases. The disease may reduce yield as much as 40%, and also may affect tuber specific gravity. Low populations of Verticillium spp. can be very damaging to potato when small populations of root-lesion nematodes also are present.

Biological Control

Incorporation of green manure crops such as sudangrass the season before potatoes are planted can reduce early dying severity.

Cultural Control

Plant varieties resistant or tolerant to early dying, such as ‘Ranger Russet’, ‘Chiptea’, and ‘Gemchip’. Provide adequate but not excessive nitrogen, phosphorous, and potassium fertilization for optimal yields. Avoid excessive irrigation early in the season and deficient irrigation after flowering. Early dying tends to be more severe under furrow than sprinkler irrigation. Long crop rotations (greater than 5 years) to non-hosts may provide some disease control.

Chemical Control

Due to constantly changing labels, laws and regulations, the sponsors of this web site assume no liability for the suggested use of any chemicals noted in the management section. Contact your local pest management personnel for current information on labeled pesticides that can be used for the intended plant disease, insect pest or weed.