On the basis of the assessment of the effects on human health and the environment of the active substances forchlorfenuron and indoxacarb, the present Directive amends Directive 91/414/EC so as to include them in the list of active substances contained therein. Member States are required, where necessary, to amend or withdraw existing authorizations for plant protection products containing forchlorfenuron or indoxacarb as active substances by 30 September 2006.