The Asian citrus psyllid Diaphorina citri is only 2 mm long, yet it strikes terror into the hearts of citrus growers in Brazil, China and the United States. This is because it acts as a vector for the bacteria that causes Huanglongbing (HLB), commonly known as citrus greening. HLB originated in Asia and now affects most citrus groves worldwide. The disease is devastating for the citrus industry because infected trees must be eradicated.