Bud Rot .. How to identify it

Ok peeps.

Currently growing Big Budah's Cheese indoor under 4 * 600W HPS-HID lamps in a (12 x 12)ft room. The walls are painted white with matt emulsion. There is extraction through the ceiling using an 8" extractor and there is also extraction through a 10" acustic box fan on the floor which becomes bi-directional if necessary which is ducted to another room. The temperature of the room is no more than 28C and no less than 19C. The humidity seldom exceeds 48% and is often constantly around 44%. The air intake is via an open window at the back of the grow space behind the crop. It has rained outside and and the humidity had begun to rise a little during the downpoor, adjusting the 10" out-take compensated for this.

Recently there has been a minor infestation of white fly on around 10 plants which has been contained and eradicated using around a common greenhouse insecticide. The plants look near perfect health and appear to be going through the right stages of development.

The problem is a Browning appearance occuring where the Stigmas emerge from the Calyx. This appearance is symetically uniform through a few plants. I am wondering ir it is normal for this strain. I somehow don't think it is. It doesn't look like a growth. I don't have a microscope. I will, however, take a few pics as soon as I can borrow a tripod to get a steady close up shot.

How do bud rot spores spread throughout a plant?

How do I identify bud rot?

Are there and links to pics of bud rot that anyone can drop inks to that I can use to compare?

Any info will be appreciated.
Many thanks...

This is the best pic I have currently. You can't see much, but if you are familiar with the condition then you might already be able to identify the problem. Stand by for more pics.

shouldnt be bud rot mate not if ur humidity only reaches 40/44% iv heard thats the ideal humidity for drying my humidity is curently runing at 60/65% im into the 3rd week of flower and there is no sign of rot at the moment fingers crossed that is

Thanks rood32.

Now that the buds are more developed I can see that the Calyx are brown and the hairs are white. It isn't bud rot after all! Though one or two are very well along in bloom and have 18-28% brown stigmas. Those premature finishers are a little spindally and look like they might almost produce 1oz between them once dry.

Bud rot is easy to detect on most plants.

Look for one or more leaves in the middle of the bud that have lost some color or are drooping slightly. If a slight tug detaches the leaves then look at the base of the stem (leaf stem). Mold as I have experienced it starts on the inside so dying leaves are the first sign. If the leaf looks like it died from the base of the stem out then you may have problems. If caught early removing the infected area or whole top should fix it.

HI just putting plants into bloom room.Not sure if you leave inlet/outlet fans on when lights are off if anyone can help be grateful.Five lovley big healthy white widow plants cant wait for harvest.First timer so far so good.theduts????????????????????thanks