Crab apple tree showing dsitress
Hi, your leaves are infected with a rust disease (cedar-apple rust or cedar-hawthorn rust). You may see a fair amount of leaf drop this spring. Rake up and dispose of as many infected leaves as possible to reduce the amount of innoculum available to infect the alternate host- Eastern red cedar. Weather is a large factor determining the severity of the disease year-to-year. Repeated severe infections can weaken the tree and cause dieback.