Important update on Blocker fungicide in potato

In mid-December 2025, AMVAC Chemical Corporation, the manufacturers of the fungicide Blocker (pentachloronitrobenzene, PCNB), decided to stop producing Blocker 4F and 10G. In effect, this concludes production of Blocker for the future. The Blocker that is on the shelves at this time is all that will be available for future use. It is estimated that this will leave potato growers with a supply that may satisfy only 25-33% of the potato use demand in 2026.