I agree with the previous comments that it is a matter of management and human relations at least as much as a technical problem. However, I would suggest that, for some at least of the technical problems you report, you might get some help from the Perl::Critic
module, at least if you succeed in convincing your team to use it.
You might also want to buy and make available to your team Damian Conway's Perl Best Practices book. Really an excellent book. I might not necessarily agree with every single one of Damian's recommendations, but, by far, most are very useful and the rationale for them is very well explained.