Several lilies that I planted last year have yellowed from the bottom of the stem (about 4 feet tall), gradually turning black, with the already set bulbs falling off. I have cut down the stalks in an attempt to stop this infestation, but to no avail. All the bulbs planted this past fall have/ or are developing this same disease. I've read the latest postings about disease and haven't seen this one described. I hope that someone can help. So far, I've cut down to the ground 10 orientals in an attempt to control this disease/scourge! Help!!