Invasive flies have never been worse in Pennsylvania’s mushroom capital, homeowners say. But eliminating them is a challenge

PHILADELPHIA — When Brendan Nerney wakes up, it's not the sound of his alarm clock he dreads, but the dull buzzes from bug zappers strung throughout his Chester County home. Throughout the historic Avondale property, flies gather in black masses across the windows, while flypaper traps, once a crisp white, are instead blotted out with hundreds of the tiny insects. "There's flies in the exhaust …