Rosette buds will also develop sooner on young trees that are interplanted with older infested trees. It takes two to three years from the time rosette bud mites are first introduced to a field before they cause a problem. Rosette bud formation. At bud break, old rosette buds which were formed the preceding season crack open. The mites inside are released and move to healthy buds which are in the process of opening.
Mites begin to feed at the base of the tiny new needles at the tip of the expanding bud.
This tip is the growing point of the shoot, and will form the bud and shoot that will grow the following season if mites are not present. The mites work their way into the bud's growing point. As the bud scales form, they are trapped inside the developing bud where they are protected from the environment. The mites continue to feed, and start to reproduce. By June, a cavity begins to form between the bud scales and next season's developing shoot.