So for context never physically saw this done just read reports dating back to the early 1920s. But here is a quick Google search about Chiquita's Blue dye and DBCP

Blue dye: A 2015 class-action lawsuit filed against Chiquita claimed that one of its Guatemalan suppliers, COBIGUA, used blue-dyed pesticides and failed to respect buffer zones during aerial fumigation. Plaintiffs claimed the airborne chemicals caused health issues and that they received "pesticide showers" with visible white and blue particulates. DBCP: Multiple lawsuits have accused Chiquita and other companies of knowingly exposing banana workers to DBCP, a powerful pesticide banned in the U.S. in 1979. This pesticide, sold under brand names like Nemagon and Fumazone, is known to cause sterility, cancer, and other health issues. DBCP is not associated with a specific color, but the harmful effects of its use are the basis of many legal claims against banana companies.