I am taking care of a friend's house while she is out of town for the summer. She has a fruit tree in the back yard (I believe it is an orange tree) that has had an issue with shriveling leaves since the time she left. The leaves are not dry and crumbly, just shriveled. At first, I strongly suspected it was getting too much water - she had it set for very good flow for 30 minutes 4 times a week - so I cut back on that considerably to where I am now at a modest flow for 20 minutes 3 times a week. But it is not getting any better and may be getting slightly worse. I also noticed some of the leaves are getting discolored and chewed up. Am I dealing with a pest / disease problem rather than a watering issue? Some of the leaves look real good. See pic. Thank you in advance!