Why did george washington authorize a campaign to wreak "total destruction and devastation" on the iroquoian villages of central new york in 1779?

To deny the British soldiers a vital life line of food supplies and secure the western frontier

The scorched earth policy was calculated to deny the British military led by Niagara a vital source of food supplies as it were that the Indians were the granary of the British. Washington also calculated that supplies from Quebec and London would be long due, and thus would grant him success. in addition, he wanted to protect the western frontier from the series of attacks by the Indians.