ON THE PARASITIZATION OF THE LADYBIRD COCCINELLA-SEPTEMPUNCTATA L (COL, COCCINELLIDAE)

The present study deals with entomoparasites of Coccinella septempunct ata L. in cereals, mainly in winter wheat. Sections of monthly sampled adult ladybirds during one year in different habitates at Staaken (Be rlin) gave two peaks of parasitization with Perilitus coccinellae (Sch rank) (Hym., Braconidae): (1) 33% in March (hibernation site); and (2) 12.5% in June (winter wheat). Populations of the ladybird investigate d during the seasons in 1993 and 1994 in winter wheat at three locatio ns (Berlin-Staaken, Flaming, Magdeburger Borde) showed a similar sharp increase in degree of parasitization with Perilitus coccinellae in th e second half of June. Maximum of parasitization reached from 12.3% (F laming, 1993) to 25% (Borde, 1993) and was a result of the act of the first newly emerged adult wasps. Main parasite of the coccinellid pupa e was Phalacrotophora fasciata (Fallen) (Dip., Phoridae) with parasiti zation rates between 4.9% (Borde) and 20.2% (Flaming). Oomyzus scaposu s (Thompson) (Hym., Eulophidae, Tetrastichinae) was found only at two locations with low rates: 0.9% (Flaming) and 1.4% (Berlin). Experiment s in climatic chambers with alternating temperatures gave new results for the effect of Perilitus on the fertility of matured female ladybir ds. At relatively high temperatures (25 degrees C middle of day) daily numbers of coccinellid eggs increased for a period of a week immediat ely after parasitization. Though mortality was high (70.6%) at this co ndition, half of the surviving females began egg deposition 12 days af ter emergence of the Perilitus larva.