VKA was a plant hormone used in military defoliants.

Evidence

VKA was a plant hormone, 2,4-D (full name, 2,4-Dichlorophenoxyacetic acid), one of the components of a mixture that some years later came to be called Agent Orange. … Norman treated test plots with VKA mixed with diesel fuel, tributyl phosphate, and other substances, and worked out how best to deliver it to rice, wheat, and other staple crops from B-25 bombers fitted with 550-gallon tanks. — Nicholson Baker, Baseless- My Search for Secrets in the…, 324

Categorization

• XREF: This connects to historical accounts of American bio-warfare efforts during cold war.
• DEFINE: This passage provides a clear definition of VKA, relevant for understanding chemical agents.
• corroborated: 3 independent passages support this claim — Nicholson Baker, Baseless- My Search for Secrets in the…, 324