Three years ago I planted two pear trees. They came from a crappy local store called Alco. I should have but did not know better at the time. They've struggled since their start. In late summer their leaves turn black as through burnt and they curl up. The fruit is turning black too. Even though I have three years of growth invested in these trees I'm thinking about pulling them and starting over with better quality stock. Since this could be a fungus or something that resides in the soil I'd likely cover the soil over with plastic, bake it in the sun to kill of any microbes and then begin anew the next year with lots of compost and new trees. Arg!!!