Corruption: >Corruption is a form of dishonesty or a criminal offense which is undertaken by a person or an organization which is entrusted in a position of authority, in order to acquire illicit benefits or abuse power for one's personal gain.
There's nothing intrinsically wrong with companies trying to influence government policies. It's only a problem when government officials abuse their office for personal gain (eg. taking bribes). In this case it's not really obvious that such improper behavior has occurred, other than a vague kneejerk reaction of "pesticides bad, therefore the only possible reason why the regulators approved it was that they were corrupt".