By Daisy Yuhas This story is part of a series by Public Health Watch and MyRGV.com. Puente News Collaborative is a partner in this collaboration. MCALLEN, Texas — When neuroscientist Kelsey Baker hears the low buzz of planes over her home in the Rio Grande Valley, she grabs her dog and hurries indoors. The drone means the crop-dusters are back, spraying pesticides over the citrus, melon and other crops that surround her planned community. Baker …