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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetic Improvement of Cool Season Food Legumes

Location: Grain Legume Genetics Physiology Research

Title: Rhizoctonia root rot of lentil

Authors
item CHEN, WEIDONG
item PAULITZ, TIMOTHY
item MCGEE, REBECCA

Submitted to: Pulse Pipeline
Publication Type: Popular Publication
Publication Acceptance Date: February 2, 2013
Publication Date: February 2, 2013
Citation: Chen, W., Paulitz, T.C., Mcgee, R.J. 2013. Rhizoctonia root rot of lentil. Pulse Pipeline. XII:2.

Interpretive Summary: Rhizoctonia root rot is a soilborne disease of lentil. Cool and wet soil conditions favor the disease. Rhizoctonia root rot has been a sporadic problem of lentil, but its incidence has been on the rise in recent years in the northern part of the Palouse region. The disease starts as reddish or dark brown lesions on lentil plants near the soil line, and develops into sunken lesions and may girdle the stem. Root lesions usually have a sunken and wet appearance. Severe constriction of the root may develop and pinch off the roots. Infected plants become stunted and leaves turn yellow progressing upward. Lentil varieties are known to have different levels of resistance to Rhizoctonia root rot. In a recent preliminary screen for resistance to Rhizoctonia root rot, Morena lentil outperformed Merrit and Pardina cultivars. Morena lentil is a recently released cultivar. It has taller plants and better yields than other lentils. Resistance to Rhizoctonia root rot could be part of the reason for the superior performance of Morena lentil. Morena lentil is recommended for managing Rhizoctonia root rot.

Technical Abstract: Rhizoctonia root rot is a soilborne disease of lentil caused by the fungal pathogen Rhizoctonia solani, and is favored by cool (11-19 C or 52 - 66 F) and wet soil conditions. The disease starts as reddish or dark brown lesions on lentil plants near the soil line, and develops into sunken lesions and may girdle the stem. Root lesions usually have a sunken and wet appearance. Severe constriction of the root may develop and pinch off the roots. Infected plants become stunted and leaves turn yellow progressing upward. Management of the disease is mainly though crop rotation with cereal crops, well-drained soil and tillage. Fungicide seed treatments can protect seeds from seed rot and pre-emergence damping off caused by Rhizoctonia solani. Resistant lentil varieties should be planted in fields with a history of Rhizoctonia root rot. In a recent preliminary screen for resistance to Rhizoctonia root rot, Three lentil cultivars (Merrit, Morena and Pardina) were tested for resistance to Rhizoctonia root rot. Morena lentil outperformed the other two cultivars against Rhizoctonia root rot. Morena lentil is a recently released cultivar, and has taller plants and better yields than other lentils. Resistance to Rhizoctonia root rot could be part of the reason for the superior performance of Morena lentil. There are concerns about its susceptibility to Stemphylium blight. However, we believe the resistance to Rhizoctonia root rot outweighs the susceptibility to Stemphylium blight. The reason is that Stemphylium blight is a late season disease and our weather conditions in the Palouse region in the late season are not favorable to Stemphylium blight. But our usual cool and wet spring weather favors Rhizoctoina root rot. Morena lentil is recommended for managing Rhizoctonia root rot.

Last Modified: 7/28/2014
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