ARS | Publication request: MORE ON IRIS YELLOW SPOT

Submitted to: Onion World
Publication Type: Trade Journal
Publication Acceptance Date: July 31, 2005
Publication Date: December 1, 2005
Citation: Schwartz, H.F., Gent, D.H., Fichtner, S. 2005. More on iris yellow spot. Onion World. p. 6-9.

Interpretive Summary: Iris yellow spot, caused by Iris yellow spot tospovirus, is an emerging disease of onion in the U.S. and world. Yield losses vary, but may range from undetectable to nearly 100% in onion seed crops. An epidemic of the disease in Colorado in 2003 is estimated to have costs growers $2.5 to $5 million in reduced farm receipts alone. Little is known about the disease cycle and epidemiology of iris yellow spot, but recent research has identified important inoculum sources of the pathogen, cultural practices that reduce the incidence of disease, and cultivars with moderate levels of resistance to iris yellow spot. Successful management of iris yellow spot requires growers to integrate as many management strategies as possible to reduce disease incidence and severity to an economically-acceptable level.

Technical Abstract: Iris yellow spot, caused by Iris yellow spot tospovirus, is an emerging disease of onion in the U.S. and world. Yield losses vary, but may range from undetectable to nearly 100% in onion seed crops. This article presents recent advances in understanding the etiology, epidemiology, and management of this disease. Little is known about the disease cycle and epidemiology of iris yellow spot, but recent research has identified important inoculum sources of the pathogen, cultural practices that reduce the incidence of disease, and cultivars with moderate levels of resistance to iris yellow spot. Successful management of iris yellow spot requires growers to integrate as many management strategies as possible to reduce disease incidence and severity to an economically-acceptable level.