Well, wouldn't it be at the time God placed the curses on Satan, Adam and Eve as a direct consequence from Adam's first sin?
Well, in Gen.3:17 God did tell Adam that the ground would be cursed for his sake, but that doesn't fit the description of the state of vanity and bondage to corruption of the earth that Paul was speaking of in Romans 8.
This Scripture does speak of a time when God shook the earth, and placed it in bondage:
Jer 4:23-28
23 I beheld the earth, and, lo, it was without form, and void; and the heavens, and they had no light.
24 I beheld the mountains, and, lo, they trembled, and all the hills moved lightly.
25 I beheld, and, lo, there was no man, and all the birds of the heavens were fled.
26 I beheld, and, lo, the fruitful place was a wilderness, and all the cities thereof were broken down at the presence of the LORD, and by His fierce anger.
27 For thus hath the LORD said, The whole land shall be desolate; yet will I not make a full end.
28 For this shall the earth mourn, and the heavens above be black: because I have spoken it, I have purposed it, and will not repent, neither will I turn back from it.
KJV