I'll add my 2¢ worth at the risk of appearing foolish, BUT, it seems (to me) from looking at all these losses there's one common denominator-: wet, wet & more wet. I've looked at Greg's numbers + Dave's and several others; and it looks like there are abnormal rainfall amounts in most if not all of these areas. Here locally June and July have been almost catastrophic with up to 20+ inches of rain. Then if that's not bad enough the humidity has been almost suffocating to work out in and even breath! All of these can and do lead to bacterial soft rot.
I'd like to comment also on certain Keppel irises: Midnight Oil & Kitty Kay will rot here no matter what I do. Happenstance, Crowned Heads, Cross Current & others will grow and bloom no problem period!
These thoughts are something I've been wondering about, and felt the impulse to add them here. I'm sure there are plenty others out there. And mine aren't 'exactly rocket science'.