The correct option is D Phytophthora infestans
Phytophthora infestans is an oomycete that causes the serious potato disease known as late blight or potato blight. Late blight was a major culprit in the 1840s European, the 1845 Irish and 1846 Highland potato famines. The organism can also infect tomatoes and some other members of the Solanaceae.At first, the spots are gray-green and water-soaked, but they soon enlarge and turn dark brown and firm, with a rough surface.
The stem, black and cereal rusts are caused by the fungus Puccinia graminis and are a significant disease affecting cereal crops.
Plasmopara viticcla causes downey mildew in grapes.
Phytophthora palmivora causes bud-rot of palms, fruit-rot or kole-roga of coconut and arecanut.
Therefore, the correct answer is option D.