Might be a frost or a bug issue? I think i know what you mean...mine sometimes aren't fully formed because the stupid Rose Chafers LOVE to feed on the flowers (they bloom right when they are at their max). When they chew on it, it must damage the flower head some, so part of the fruit is then damaged, yet it still forms. I usually just spit out the bad part.

The way I tell the difference is bumble = hairy butt and carpenter = smooth/shiny butt (technically called "hairless"). I had always thought it was "butt" & not "abdomen", but thanks to Google, I found how wrong I was terminology wise, LOL. I always thought the abdomen was the center of the bee, not the bottom part. From the attached link: General Bumble Bee Information The "Bumble Bee" is a big, hairy, black and yellow bee whose size can range from 3/4 inch to 1 1/2 inch. This insect is often mistaken for a carpenter bee, which closely resembles the bumble bee in appearance. Carpenter bees have a shiny and smooth abdomen as opposed to the fuzzy abdomen seen on a bumble bee. The pic posted by terrene is a carpenter bee. Here is a link that might be useful: Bumble Bee Biology

what does it matter... there isnt anything you can do about it ... in spring.. any improperly hardened off parts.. will have blackened... and you can prune it out ... this is one reason i NEVER fert trees.. shrubs.. and conifers ... they are not children.. they dont need to be fed ... ever .. IMHO ... if something is lacking in the soil.. based on a high level soil test.. that has nothing to do with 'feeding babies' ... was yours a recent transplant.. if so.. and you didnt bare root the plant.. you also have incorporated fert .. so you may have doubled up on such.. by adding more .... ken ps: i am going to bet.. its not going to be a huge problem in your zone ... compared to froze solid MI in winter ...

Mine come out of the acute symptoms, particularly the leaf necrosis, but they remain stunted and the leaves have a mosaic of chlorotic regions. I'll post some pics later. What makes me suspect the seeds is that all the plants come down with it at exactly the same time, and different succession plantings come down with it at exactly the same maturity, regardless of weather conditions. But it certainly could be an insect vector - aphids or maybe something else. The aphids don't even have to feed to transmit a virus, as long as they probe the leaf, they can transmit it. So even if the plants are coated with insecticide, the aphids can infect them. I'm going to stop by the local extension tomorrow and see if they can give me a definitive ID. I'll post their answer tomorrow evening. BTW, where are you guys located? I'm in SE Michigan. I'll ask at the extension, if this is a virus or some other disease, if they know what regions are affected. Maybe that could help zero in on whether it's Burpee's seeds or not. Thanks.