I moved to California from the land of never ending rain and I am not familiar with flora of this climate. In addition no experience in gardening. Year ago we moved to the apartment with the small patio. There were few plants and some bush which I lovingly watered. Couple of weeks back I noticed a flower bud on the said bush that looked like it belongs to Pomegranate tree. Unfortunately two days later i noticed black spot on it and then it dropped. In addition i noticed some changes (see attached photos). I searched google for an answer but I can find what is bothering the tree. I cant see any insect except few lacewing eggs and no ants. Leaves and twigs were red leaves are have sticky clear sap present but again I cant see any insect. Any advice will be greatly appreciated.