Introduction of exotic parasites for biological control of the birch leafminer (Hymenoptera: Tenthredinidae) in the Middle Atlantic states [Lathrolestes nigricollis, Grypocentrus albipes, Phanomeris]

Approximately 9,600 Lathrolestes nigricollis (Thomson), 2,600 Grypocentrus albipes , 50 Phanomeris sp. probably catenator , and 550 Chrysocharis nitetis were released in the Middle Atlantic states from 1976 to 1982 in efforts to establish populations for biological control of the birch leafminer, Fenusa pusilla . Releases of these parasites, all of European origin, were made in birch (Betula spp.) stands at 16 locaties in Delaware, Maryland, New Jersey, and Pennsylvania. Two species, L. nigricollis and C. nitetis , are established in Pennsylvania.