Natural Control of Diprion similis, Htg., in Poland during 1936

Abstract

During a search over Europe for species of the genus Diprion an infestation of Diprion similis was located in Poland at Orle, near Wlosclavek. The infestation was remarkable in that the prepupae which had spun up in the autumn of 1935 did not proceed with normal development in the following year, but remained in a prolonged dispause. An opportunity was thus afforded of studying at length the control exerted by biotic factors on the prepupal stage of the host sawfly.