Multiple choice Which of the following is not a correct match? Root knot disease – Nematode Heterodera marioni Smut of bajra – Helminthosporium sacchari Covered smut of barley – Ustilago nuda Late blight of potato – Phytophthora infestans Reveal answer Fill a bubble to check yourself C Correct answer Explanation Covered smut of barley is caused by Ustilago hordei.