Still on about war crimes that aren't actually war crimes in a world where they have yet create any concept of war crimes?
The full version of the Geneva Convention's Protocol 1, Article 54 which was quoted earlier
"It is prohibited to attack, destroy, remove, or render useless objects indispensable to the survival of the civilian population, such as foodstuffs, agricultural areas for the production of foodstuffs, crops, livestock, drinking water installations and supplies, and irrigation works, for the specific purpose of denying them for their sustenance value to the civilian population or to the adverse Party, whatever the motive, whether in order to starve out civilians, to cause them to move away, or for any other motive."
By removing the civilian population the resources are no longer indispensable to their survival, completely eliminating the relevance of the Article. The Article on trapping supplies is also irrelevant because no traps were used nor were the supplies offered, they were rendered unusable to bandits and raiders after the area was deemed unsafe and the residents relocated. Furthermore, the "poison" was tailor made to only last 10 days, by the time she would've gone on trial for the crimes they would have no evidence other than the testimony of the victims. Victims which were more victims to their CO's suicidal march with reliance on pillage, the use of a "protective emblem" (such as a religious symbol, like a cross), and failure to care for the sick and wounded, 3 more war crimes.
And of course, they have no concept of war crimes in that world.