Diseases of Lentils

Photo: Morrall	Picture description Ascochyta lesions on leaflets.	Photo: Morrall	Picture description Ascochyta infected vs clean seed.
Photo: Morrall	Picture description Affected crops may be severely blighted and seed becomes shrivelled and discolored.

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Management strategy
Most new cultivars are resistant to this Ascochyta disease which is specific only to lentils. The Ascochyta disease is readily seed-borne and seed treatments help. Crop rotations, resistant cultivars, disease-free seed combined together give good disease control.

Seedling Blight.
Rhizoctonia solani

What to look for?
Rhizoctonia blight is a problem in cold dry soils when lentils are grown in reduced rotations. Herbicides such as residual 2-4 D from fall or spring "burn off" residual trifluarilins, group 2 herbicides and clopyralid particularly in dry seasons may cause significant crop damage or crop failure.

Photo: Morrall

Picture description
Rhizoctonia injured seedlings.

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Management strategy
Follow 3 - 4 year rotations and exercise care in herbicide use.

Stem and Root Rot.
Rhizoctonia solani, Fusarium sp. and Botrytis sp.

What to look for?
If herbicide residues can be ruled out, many unthrifty stands may be traced to cool or wet growing conditions where one or all of the above mentioned fungal diseases may be involved.

Photo: Kharbanda

Picture description
Slow growing damaged seedlings.

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Management strategy
Follow 3 - 4 year crop rotations and use recommended seed treatments.

Stem Rot.
Sclerotinia sclerotiorum

What to look for?
Sclerotinia's destructive when lentils are grown in the wetter more humid areas of Alberta. Lush stands of the crop may become severely diseased under humid conditions.

Photo: Zimmer

Picture description
Sclerotinia injury.

Photo: Tsukamoto

Picture description
Crop destruction by Sclerotinia.

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Management strategy
Lentils are a crop suitable for the drier areas of the province. Lentils are not suited for growing in normal years in the wetter areas of Alberta.

Gray Mold and Pod Rot.
Botrytis cinerea

What to look for?
Late sown crops in cold wet August growing conditions are most susceptible. Losses maybe up to 50% in yield with considerable loss of quality.

Photo: Morrall

Picture description
Botrytis injury.

Photo: Morrall

Picture description
Botrytis pod injury.

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Management strategy
Again, a crop better suited to dry weather cycles or drier areas of the province since lush stands and cold wet weather favor Botrytis infection.

Anthracnose.
Colletotrichum truncatum

What to look for?
Yellow patches first appear in the field similar to those caused by Botrytis and Sclerotinia however, plants killed by Anthracnose have blackened stems. The blackening is caused by tiny microsclerotia the resting stage of the Anthracnose fungus. Seed transmission is a factor but destructive disease levels result from a build up in the field.

Photo: Morrall

Picture description
Early infection.

Photo: Morrall

Picture description
Heavy Anthracnose infection showing black stems.

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Preventative measure
Sclerotia on the stubble persists for five years or more. Crop rotation of four or more years along with foliar fungicides are effective controls.

Photographs and information assembled and prepared for ARD by Dr. Ieaun R. Evans Agri-Trend Agrology Ltd.

Diseases of Lentils

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