Ascochyta Disease in Lentils
Ascochyta blight, caused by the fungus Ascochyta lentis, is a serious disease of lentil causing yield losses and severe seed discolouration in epidemic years. Yield losses may be as high as 50% in susceptible cultivars. Additional economic losses occur due to loss of grade.

The ascochyta fungus has become much more aggressive n recent years. The cultivars Laird is now as susceptible as the cultivars Eston and Richlea.

Appearance: symptoms appear on leaves, stems and pods as light gray o tan coloured sports, sometimes with a darker margin. The centres of spots are often speckled with tiny, black fruiting bodies. When disease becomes severe, premature leaflet drop may occur and the crop takes on a distinctly blighted appearance. Seed discolouration develops later in the season after pods are infected. Seeds become brownish purple in colour and may be shriveled. In moist weather conditions, discolouration can continue to develop even after the crop is swathed.

Disease Cycle: The fungus over-winters in seed and infected lentil crop residue. Infected seed is often discoloured but sometime-healthy looking seed may also carry the fungus.

When infected seed is planted, small proportions of the seedlings emerge diseased. The fungus then spreads from plant o plant by rain-splashed spores. The disease is favored by moist conditions. Frequent showers can result in an epidemic.

Disease Control:
a) Use disease-free seed - Many epidemics originate from infected seed. There is no safe level for seed infection. Under favorable environmental conditions, even seed as low as 1-2% ascochyta inf4ected can result in an epidemic. An accredited seed lab using an agar plate test can determine the level of ascochyta in seed. The fungicide Crown has recently been registered as a seed treatment for ascochyta in lentil, but will not protect the crop throughout the growing season.
b) Crop rotation - Allow three years between lentil crops on the same field and avoid planting next to the previous year's lentil fields.
c) Chemical control. Bravo 500 is registered as a foliar spray for the control of ascochyta blight and anthracnose on lentil. More than one application may be necessary, starting at early bloom.
d) Resistance - The cultivars Indianhead, CDC Matador, and CDC Redwing have some resistance and suffer less yield loss than susceptible varieties.

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