Virgil

Parch'd was the grass, 

  and blighted was the corn . . .

[F]or Sirius, from on high, 

With pestilential heat infects the sky: 

My men -- some fall, the rest in fevers fry. 

From John Dryden's 1697 translation of Virgil's Aeneid, which tells the story of the founding of Rome by the Trojan hero, Aeneas.  The first line of the Aeneid -- "Arma virumque cano," or "Of arms and the man I sing" -- inspired the title of George Bernard Shaw's 1894 play, Arms and the Man.  

In ancient Rome, the hot, sultry "dog days" of summer -- named for Sirius, the "Dog Star" -- ran from July 24 to August 24.  In those days, Sirius (the brightest star in the sky) rose at about the same time as the sun during those dates.  That is no longer true, of course, owing to precession of the equinoxes -- but you probably knew that already.