HPIPM:Verticillium Wilt

Author: Ned Tisserat and Gary Franc"

Taxonomy

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

Scientific Name

Verticillium dahliae

Scientific Name Synonyms

Verticillium tracheiphilum

Verticillium ovatum

Common Name

Verticillium wilt

Cause

Verticillium albo-atrum

Occurrence

Verticillium wilt is widespread in the High Plains but has largely been controlled by the use of resistant varieties.

Key Symptoms

• Stunting and wilting,
• Leaves on upper stem may be slightly twisted with a pinkish tinge
• Leaflets may develop v-shaped chlorosis
• Internal root tissue turns yellow-brown, although this is not always a reliable symptom
• Plants should be sent to laboratory for confirmation
• Plants may die in mid-summer

Pathogen

This fungus persists in the soil for years. It can also be carried internally and externally on seed.

Management Approaches

Use resistant varieties. See the following sources for varietal information:

• University of Wisconsin forage pages http://www.uwex.edu/ces/forage/pubs/varinfo.htm
• University of Wyoming Alfalfa Disease Management Publication B1136 http://ces.uwyo.edu/PUBS/B-1136.pdf
• Alfalfa should follow corn or small grain in a rotational sequence. Never follow alfalfa with alfalfa.
• Avoid injury to crowns and roots including cultivation and excessive traffic

The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.