Management of Stemphylium leaf blight disease of onion


2015 to 2018


Onions are an important crop in New York, accounting for 97% of the onion production in the northeastern United States and ranked 6th for onion production across the country with an annual area of over 10,000 acres and sales of approximately $52 million. Stemphylium leaf blight has emerged as a major disease of onion in NY and Canada in recent years.


Growers of onion in NY State and CCE educators have noticed increased severity of leaf blight in many onion crops in the last 5 years. Premature senescence of onion crops due to leaf blight is believed to cause considerable loss in yield and quality of onion.


Initial funding has been sourced from the Onion Research and Development Program to conduct surveys which identified Stemphylium leaf blight as the main cause of leaf sensescence in NY onion crops. Further funding has been sourced in 2016 through SCBG, NIFA and Federal Capacity Fund to conduct on-going research to develop an integrated management strategy.


Work during 2016 has indicated a high level of fungicide resistance in the Stemphylium population to one of the main fungicides used (azoxystrobin). This will require growers to develop amended fungicide programs to achieve better control of this disease. Further funding will develop an integrated management program for Stemphylium in onion in NY.

Submitted by: 

  • Pethybridge, Sarah J

Researchers involved: 

  • Hay, Frank S
  • Pethybridge, Sarah
  • Hoepting, Christine A

International focus: 

  • United States of America

United States focus: 

  • New York