Repellent compositions and genetic approaches for controlling huanglongbing

A method for controlling Huanglongbing (HLB) in citrus plants comprising genetically modifying the citrus plants so that they express at least one isolated gene encoding a polypeptide having β-caryophyllene synthase to produce additional β-caryophyllene in order to repel Diaphorina citri and/or Tryoza erytrae psyllid insects so as to control HLB in the genetically modified plant, wherein the isolated gene has SEQ ID NO:

• 1 and encodes a β-caryophyllene synthase (BCS) polypeptide that produces the additional β-caryophyllene to repel Huanglongbing (HLB).