Lentil Disease Diagnostic Series: Aphanomyces Root Rot

Authors: Porter, Lyndon

Submitted to: Extension Reports
Publication Type: Experiment Station
Publication Acceptance Date: 1/8/2019
Publication Date: 2/1/2019
Citation: Porter, L.D. 2019. Lentil Disease Diagnostic Series: Aphanomyces Root Rot. Extension Reports. PP1913.

Interpretive Summary: A short and concise disease diagnostic card was developed to help growers rapidly diagnose Aphanomyces root rot on lentil through descriptions and color photographs of symptoms commonly associated with the disease. The card also provides important factors that favor disease, facts regarding how to manage the disease, and describes a disease that could potentially be mistaken in appearance for Aphanomyces root rot.

Technical Abstract: Aphanomyces root rot caused by Aphanomyces euteiches is one of the most damaging diseases of lentil. The following symptoms typically are associated with this disease: 1) caramel-brown rot on below-ground stem and roots, 2) stem rot may extend slightly above the soil line, 3) yellowing progressing from lower canopy upward, and 4) early season stunting and premature plant death. Factors favoring disease development include: 1) cool wet spring conditions, 2) low-lying areas of fields where soil moisture levels are high, and 3) short rotations with peas and lentils which are both susceptible hosts. Important facts about Aphanomyces root rot are: 1) chickpea, cereals, and faba bean are not hosts of the pathogen, 2) the disease often occurs in a complex with other root rot diseases, 3) seed treatments and genetic resistance are currently not effective, 4) pathogen can survive for many years (20 years) in soil without a susceptible host, and 5) the disease can often be confused with Rhizoctonia root rot.