Loose Impediments: "Loose impediments" are natural objects including:
stones, leaves, twigs, branches and the like,
dung, and
worms and insects and casts or heaps made by them, provided they are not:
fixed or growing,
solidly embedded, or
adhering to the ball.
Sand and loose soil are loose impediments on the putting green, but not elsewhere.
Snow and natural ice, other than frost, are either casual water or loose impediments, at the option of the player.
Dew and frost are not loose impediments.
©USGA, used with permission

