BIOMETRICS AND IMPORTANCE OF THE EGG MASS OF THE PROCESSIONARY, THAUMETAUPOEA PITYOCAMPA SCHIFF ON THE CEDAR OF THE ATLAS, CEDRUS ATLANTICA MANETTI

The study led on 113 egg mass of Thaumetopoea pityocampa coming from various cedar plantations of the North of Algeria showed lengths of egg mass of the population of the processionary on the cedar of Chélia more consequent (29+ 6mm) that those of the egg mass collected in the cedar plantation of Chréa (23+6mm). The frequential analysis lengths of the egg mass highlighted 5 classes for the batches collected in the three prospected sites. The data collected highlight a difference very highly significant between the batches tested (p=0, 0001). The egg mass coming from the prospected sites reveal a full number of 22237oeufs with an average of 175+49 eggs per laying. The fruitfulness of the population evolving/moving on the cedar plantation of Chréa is more consequent with that in the site of Theniat El Had. A diversity of 3 species of chalcidiens parasitoïdes pertaining to the order of Hyménoptères was noted starting from the analyzed biological material. The species Baryscapus (Tetrastichus) servadeii, Ooencyrtus pityocampa and Trichogramma embryophagum are active on the various examined and analyzed samples. The rate of calculated parasitism is very different between the localities, does not exceed 16,66% in the populations sampled with a predominance of Baryscapus servadeii. The combinations of the presence of the three parasitoïdes are noted on the biological material examined with a prevalence of the species Baryscapus servadeii. In the sites of Chréa and Theniat El Had, only the alternative O. pityocampae with T.embryophagum was not noted. The ends of the layings, badly protected by the scales are sought by the parasitoïdes. The parasitoïdes, O.pityocampa and T.embryophagum seem to be recognized not to return in specific competition. These antagonists seem to recognize parasitized eggs. On the basis of result obtained, an alternative of fight containing the species Ooencyrtus pityocampa proves to be interesting and very debatable.