I have an Amelanchier that will leaf out in the spring and flower, then as the summer progresses the leaves turn yellow and fall so that by fall the plant is mostly bare. This happens every year. The plant gets full sun for most of the day and is planted in sandy loam soil. My yard has an irrigation system so the plant does get some water. Not sure if the problem is insect damage or fungus related. I am including three pictures. Thank you in advance. Craig Ashworth