All species' larvae are believed to possess three early sap-feeding and two later tissue-feeding instars. Sap-feeding instars initiate a slender, serpentine to wedgeshaped, subepidermal tract on the underside of the leaf. The succeeding two instars continue feed in the spongy parenchyma, which, by the third instar, is enlarged to form a blotch
(2). Usually two or three generations per year.