One of the main concerns of the Việt Minh was the threat of hunger. In 1944-1945, a famine had most likely resulted in the deaths of over one million Vietnamese in the Red River Delta. While the French and Japanese were blamed for this famine, the Việt Minh knew that they would lose valuable people and be held at least partially responsible if famines were to strike again (Gunn, Lentz).

The Việt Minh were very concerned that the French might attack rice and vegetable crops in areas under Việt Minh control. Such actions would weaken Việt Minh partisans and might encourage them to move to French controlled territory.

Above you can see a partial map of the Viet Bac showing its relief. Compare it to a Google map showing the reported use of biological weapons in the provinces of the Viet Bac from April 1952 to March 1953.