Structure and Parasitism of Egg-Batches of the Pine Processionary Moth, Thaumetopoea Pityocampa in the Algerian Cedar Forests.

Abstract

Today, climate change is one of the greatest threats facing forest ecosystems. It directly influences the geographical distribution of insects and increases epidemics of harmful insects. The present work took place in this context. It aimed to contribute to the knowledge of egg parasitoids that could affect the evolution of the pine processionary caterpillar Thaumetopoea pityocampa, a major forest pest in Algeria and Mediterranean countries. The study was carried out on 120 batches of eggs taken from the Atlas cedar at two sites in the Chelia cedar zone (case of eastern Algeria) in 2017. It allowed the analysis of a total of 37,943 eggs. At the first site, the hatch rate was 66%; the egg mortality rate increased at a rate of 15 %, and the parasitism rate was rather high at 18%. The second site was characterized by the parasitism rate lower by about 11%, while the egg mortality rate was relatively comparable in the order of 14% with a hatching rate of 75%. The eggs are more parasitized by Baryscapus servadeii (79%) than by Trichogramma embryophagum (17%), while Ooencyrtus pityocampae remains negligible (4%). Egg parasitoids are an important killer of Thaumetopoea pityocampa eggs.

Keywords

• thaumetopoea pityocampa
• egg batches
• atlas cedar
• egg parasitoids
• algeria.