CAIP, which is part of an ongoing effort to curb wildlife poisoning, is reinforcing the message after recent successful prosecutions involving storage or use of illegal pesticides such as carbofuran, not approved for use since 2001, and sodium cyanide, withdrawn in 2004.
A CAIP spokesman said: "Pesticide stores need to be checked at least twice a year to make sure that all products in stock are currently approved.
"Particular attention should be paid to those products whose approvals are due to expire to ensure they are used up in time. Once approval is revoked, it is illegal to hold such products in store and professional disposal is the only legal option.
"Storing unapproved products is illegal and there can be no justification. Discovery of non-approved pesticides, even an odd pack at the back of a store, will jeopardise Single Farm Payments. Enforcement officers will also be suspicious that such products may be used to illegally poison wildlife."
Pesticide approval status can be checked on HSE and Chemicals Regulation Directorate websites, or with pesticide suppliers.
A list of licensed waste contractors can be found at www.wasterecycling.org.uk
See www.pesticides.gov.uk for products with MAFF or MAPP numbers or www.hse.gov.uk for products with an HSE number. If there is no number, it is either not a pesticide or not approved.