HPIPM:Stemphylium blight

'"`UNIQ--btaxobox-00000002-QINU`"'

Stemphylium blight (Stemphylium botryosum)

Compiled by Mary Burrows, Montana State University from the following sources:

• Mwakutua, E. 2006. Epidemiology of Stemphylium blight on lentil (Lens culinaris) in Saskatchewan. Thesis, Department of Plant Sciences, University of Saskatchewan, Saskatoon. http://library2.usask.ca/theses/available/etd-04202006-174755/unrestricted/Edmore_thesis.pdf. Accessed 15 April, 2010.
• Barker, B. 2010. Stemphylium blight of lentil on the radar screen. Top Crop Manager West, March 2010. http://www.mydigitalpublication.com/publication/?i=33313. Accessed 15 April, 2010.

Cause

Stemphylium botryosum

Symptoms

Initially small, light beige lesions on leaves or leaflets leading to larger, irregularly shaped lesions that kill leaflets and branches. Prolonged moist conditions promote infection and give the upper canopy a grey-brown appearance. Old lesions appear dark brown and fuzzy, and leaves will be rolled and twisted.

Impact of Disease

Unknown.

Currently identified in Canada. Distribution in U.S. is not known.

Life Cycle of the Pathogen

Survives on crop residue. Prefers warm temperatures (>25C) and a minimum of 8 hours of leaf wetness. High relative humidity (85%) is favorable for disease development.

Can be seed transmitted.

Management Approaches

No fungicides are currently registered for Stemphylium blight control on lentil. Crop rotation will reduce inoculum.

Biological Control

None known.

Cultural Management Practices

Crop rotation, variety selection.

Host Plant Resistance

None known.

Chemical Management Program

No fungicides are registered for control of this disease.

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.