PARASITISM OF EGG-BATCHES OF THE PINE PROCESSIONARY MOTH THAUMETOPOEA-PITYOCAMPA (DEN-AND-SCHIFF) (LEP, THAUMETOPOEIDAE) IN VARIOUS REGIONSOF BULGARIA

In forests of Pinus nigra Arn. 147 egg-batches of T. pityocampa were c ollected at different locations in Bulgaria in September-October 1991 and March and June 1992. Directly after collection all batches were pu t singly into test tubes with cotton stoppers and stored under laborat ory conditions at 20-22 degrees C. Oviposition always started from the base towards the top of the needle. The emergence of egg parasitoids were controlled almost daily and they were counted and identified. The eggs from which parasitoids emerged were marked for further studies. After removing the scales and opening the eggs, the impact of the para sitoid species was evaluated by their meconia and remains. Ooencyrtus pityocampae (Mercet) was observed as the most abundant egg parasitoid, followed by Anastatus bifasciatus (Fonsc.) and Baryscapus servadeii ( Dom.). The hyperparasitoid, Baryscapus transversalis Graham was record ed for the first time in Bulgaria and the polyphagous species Macroneu ra vesicularis (Retzius) was collected in Bulgaria for the first time from an egg-batch of T. pityocampa. Trichogramma sp. was obtained in s mall amounts, too. Total mortality of host eggs varied from 34% to 48% ; the mortality rate due to parasitism was 24.5% to 38.9%. The emergen ce dynamics of the egg parasitoids was studied under laboratory condit ions, and the distribution of the egg parasitoids in the egg-batches w as recorded in detail. Additionally, the structure of the meconia of A . bifasciatus and M. vesicularis was described.