Alfalfa

Verticillium Wilt

 Ned Tisserat and Gary Franc

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:

o 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

Categories: Alfalfa, Disease, Verticillium wilt

Date: 03/01/07