Harmfulness of Alternaris species fungus on the spring mustard

It is determined the greatest losses of mustard yield at Alternaria affection are detected during disease symptoms appearance in yellow-green pod phase. 1000 seeds weight is lower on 1.0 g, yield per a plant decreased on 8.1 g, seeds energy and germination reduced on 3.0 and 20.0 %, respectively, in comparison with control. Oil and monounsaturated acids contents are significantly lower of the control (3.6 and 9.8 %, respectively), and polyunsaturated acid content is higher (on 8.8 %).