PCNB fungicides include Blocker 4F® and 10G®. PCNB is an acronym for the chemical pentachloronitrobenzene. In Indiana, PCNB fungicides are used for bottom rot, club root, and wirestem in brassica crops. Brassica crops for which PCNB products are labeled for include: Broccoli, Brussels sprout, cabbage, cauliflower, collards, kale, kohlrabi, and mustard greens. Be sure to check the label for crops and directions.
The U.S. Environmental Protection Agency (EPA) is releasing a proposed final decision for pentachloronitrobenzene (PCNB) that proposes to cancel all registrations of this pesticide. This would include all the uses detailed in the paragraph above. Why? The EPA has identified risks of concern to fish, amphibians, aquatic invertebrates, aquatic plants, birds, reptiles, mammals, and bees. Unfortunately, PCNB’s tend to bioaccumulate in the aquatic food chain. Also, the EPA has noted adverse effects on the thyroid and identified potential non-cancer risks of concern from PCNB exposure.
To comment on this proposed action, go to this link.
https://www.regulations.gov/docket/EPA-HQ-OPP-2015-0348. Once this link has been posted to the federal registry (which will presumably be soon), there will be 60 days to post comments.
Alternatives to PCNB fungicides include:
- For bottom rot, Endura®
- For club root, Omega®
- For wirestem, Cabrio® and Priaxor®.
These are all diseases of brassica crops. Again, check the label before all uses.