The
destruction of crops is a political act. The linked web search brings up entries describing when crops were destroyed as a "punishment" for being suspected allies with the enemy North Vietnamese. It's used by the Burmese and Israeli governments to punish political enemies. Self destruction of crops was used in India, by farmers, to restrict production, and thus attempt to stabilize land use patterns.
It's part of the war on drugs. It's part of the US war on Iraq. It's against the law in some places.