|Wunsch, Michael - North Dakota State University|
|Burrows, Mary - Montana State University|
Submitted to: Take your Pulse Magazine
Publication Type: Trade Journal
Publication Acceptance Date: 8/5/2013
Publication Date: 9/15/2013
Citation: Chen, W., Mcgee, R.J., Vandemark, G.J., Wunsch, M., Burrows, M.E. 2013. Towards Managing Stemphylium Blight of Lentil in the Pacific Northwest. Trade Journal Publication. 3:13-15.
Interpretive Summary: Stemphylium blight of lentil, caused by the fungus Stemphylium botryosum, has recently emerged as a disease problem in the Pacific Northwest, particularly on the recently released lentil cultivar ‘Morena’. It has been known as a devastating disease of lentil in Bangladesh and India. Due to potential negative impact of Stemphylium blight on lentil yield, we have been closely monitoring the situation of the disease on ‘Morena’ lentils since ‘Morena’ lentils went into commercial production in the 2013 growing season. This article provides detailed photos to aid identification of the disease, and an update on the development and identification of Stemphylium blight on lentil in the Pacific Northwest, and on the current research efforts and recommendations on strategies for managing the disease.
Technical Abstract: Stemphylium blight of lentil, caused by the fungus Stemphylium botryosum, has recently emerged as a disease problem in the Pacific Northwest, particularly on the recently released lentil cultivar ‘Morena’. The first step toward managing the disease is to correctly identify early signs of the disease. Stemphylium blight of lentil occurs in the middle season right after canopy closure. The pathogen likes warm temperatures. In the Palouse regions, the disease starts in late June or early July, and affects only lentil leaflets (or leaf blades). A major characteristic of Stemphylium blight is that the affected leaflets turn tan color starting near the base or the edge of the leaflets, then whole leaflets turn a tan color as they are blighted. Adjacent leaflets can look unaffected. As the disease progresses, all leaves turn a tan color, or become ‘blighted.’ Under humid conditions such as under a dense canopy, the infected leaves may turn black in color (sooty) due to production of spores by the pathogen. There are options to manage the disease. First of all, you may choose to plant resistant lentil cultivars if you want to avoid the disease completely. However, if you want to plant ‘Morena’ lentil taking advantage of its resistance to Rhizoctonia root rot and higher yield potential, the Stemphylium blight can be managed through application of fungicides that are effective against the disease. Fungicides should be applied before canopy closure. If more than one application is applied to a lentil field, it is strongly suggested fungicides with different mode of actions should be alternated to prevent potential development of fungicide resistance in the pathogen population (consult your crop advisors or county extension agents for proper and available fungicides. As time goes by and as ‘Morena’ lentil gains popularity, we will experiment and develop a more comprehensive strategy for managing Stemphylium blight of ‘Morena’ lentil. And more importantly, future lentil cultivars will be bred to include resistance or tolerance to Stemphylium blight.