Botyritis spores are everywhere. If conditions suiting their growth exist, you will see infections like this. Botyritis thrives with high humidity and poor air circulation.
Healthy plants have good natural defences against pathogens. An unhealthy plant is more susceptible to botyritis than healthy ones. Judging from the poor development and yellowed leaves, the pictured bud looks like the plant it came from was in big trouble.
Won't hurt you to smoke it, but it'll be completely unpleasant. Heat from burning will kill any spores. However, even if you inhale some live spores, botyritis will not thrive in a lung. You're breathing botyritis and many other types of spores/virii/bacteria all the time.