Which one is the wrong pairing for the disease and its causal organism?
Late blight of potato - Alternaria solani
Black rust of wheat - Puccinia graminis
Loose smut of wheat - Ustilago nuda
Root-knot of vegetables - Meloidogyne sp.
As late blight of potato is caused by the oomycete Phytophthora infestans, not Alternaria solani. Therefore, the correct answer is:option 1