Last year, about March, I planted a lovely healthy Lemon tree. It seemed happy and established when it began to lose its leaves. It was getting plenty of water and I used organic fertilizer - Bounce back. I dug a nice square hole and planted using soil and compost. In spring (August - September) it flowered profusely but the early fruit soon fell off. It is flowering again, here and there. The few leaves remaining look healthy and green. No pests have been seen and the soil pH is 7.5 (tested with a soil measuring device). I have noticed of late that two of my dogs wee there. Could that be the cause of the problem? I know that lawns develop brown patches where the dogs have urinated.