Causes for mold over stucco can be caused by poor water flow, plants to close to stucco, lack of kick out flashing on roof, areas of high humidity, as well as lack of exposure to sun and mulch level being to high or close to the stucco.

If mold is left untreated, it will slowly start deteriorating from both inside and outside. In this case the wall was left untreated and small spores have started to come through the stucco. At this point it is best to remove and replace the entire stucco. Worst case scenario is that the wood got compromised and will have to knock down the plywood as well. Also you run the probability that the interior will have to be replaced as far as drywall goes.

The type of finish one chooses will also determine how many cracks you will see. If you get a smooth finish like the one below you will be able to see more cracks. at first glance you can see 1 or 2 cracks that need repair but if you stare/zoom in at it for a while you can see it has more than 7-8 cracks 

Fixes are simple, lower the level of the dirt/mulch. always want to keep 4-6 inches clear from stucco to ground. From the wall outward 12-16 inches fill in with wash gravel to avoid constant splashing of dirt onto stucco. Also pressure wash stucco at least 3-4 times a year.

Most stucco issues are because of the lack of, improper installation, Wrong type of flashing on the roof. If the flashing is over the shingle and over the stucco then it is not installed correct as well as if it doest have a kick out to kick the water out then it will fall straight behind the stucco.

YOU SHOULD NOT HAVE A GAP OR INTERSECTION WHERE TWO DIFFERENT WALLS MEET. This will cause multiple head aches in the future. it will not only crack your stucco but the metals behind the cement will rust and if the tyvek paper is not applied well the plywood will get wet and start inflating unless you used treated. Cases like these where the gaps are open this wide you will have to tear down the stucco and sections of the plywood and 2x4's if rotten. This will result in an expensive repair, but could have been prevented if sealed with a polyurethane sealant or at least a line of mud running up and down the area.