Diseases of alfalfa (
Rhizoctonia root rot
Rhizoctonia root rot is caused by the soil borne fungus Rhizoctonia solani. Disease occurs in warm summer months causing lesions and later rot of taproots (photo 1). Rhizoctonia root rot occurs sporadically in Arizona with most recent incidences in the Parker Valley in mid summer (photo 2), but has not been a problem throughout the remainder of the year.
Improved drainage may reduce disease incidence. There are no other control measures recommended.
1 
2 
July 13 , 2006