Why will email not delete off iPhone when I delete it off desktop?

[FloridaMac]

I have mobileme for email and when I delete an email from mobileme on, say, my desktop it doesn't delete them from my other devices (ipad and iphone4) unless I actually go into email on those devices and let it update. In the past as soon as I delete an email from my desktop the red number indicator on the mail icon disappears and I don't have to go into the email. Is there any reason this may be happening? It's only recently started doing this. It's annoying. Thanks.

 

[FloridaMac]

nm