Applying pesticides in mixture can bring about an increased level of perfor
mance which can be of benefit to manufacturers who make use of this phenome
non when formulating products. The interactions that occur can also bring a
bout adverse effects on performance and possibly on the safety of the produ
ct to users, consumers and the environment. Because of this a product conta
ining a mixture of active substances must be considered by registration aut
horities. Each discipline in the regulatory process must consider the likel
ihood of an interaction occurring and, as a result, request and examine the
necessary data to support approval for that mixed product. Within the Euro
pean Community the requirements are laid down in Directives that have been
introduced to harmonise the regulatory process across Member States. The re
quirements of these Directives are described as an example of the regulator
y process. (C) Crown copyright 1999. Reproduced with the permission of the
Controller of Her Majesty's Stationery Office.