The HSE has published guidance on the regulation of pesticides following Brexit. http://www.hse.gov.uk/brexit/regulating-pesticides.htm
This is guidance on arrangements for regulation of plant protection products (PPPs), which are often referred to as ‘pesticides’, during the IP. guidance covers
Preparations for an implementation period What businesses need to know More about how things will change if the UK leaves the EU with a deal Applications for active substance approvals Maximum Residue Levels (MRLs) Applications for product authorisations Applications which have started before exit day Trading in plant protection products Information for pesticides users If there is ‘no-deal’