Scorched earth
A scorched-earth policy is a military strategy that aims to destroy anything that might be useful to the enemy while it is advancing through or withdrawing from a location. Any assets that could be used by the enemy may be targeted, for example food sources, water supplies, transportation, communications, industrial resources, and even the locale's people themselves.
Scorched earth
The U.S. employed Agent Orange, as a part of its herbicidal warfare program, Operation Ranch Hand, to destroy crops and foliage in order to expose possible enemy hideouts during the Vietnam War. Agent Blue was used on rice fields to deny food to the Vietcong.