Contribution a la connaissance de Thaumetopoea pityocampa Schiff : etude de lachenilleprocessionnaire du pin et du cedre au Maroc

Abstract EN

From 1974 to 1977, the authors studied the Pine Proces-sionary Caterpillar over its entire distribution area in Morocco.

This area is divided into three zones.

The first zone is in the region of the Rif and Middle Atlas, where the insect attacks Cedar trees and sometimes, Pine trees.

The climate of this region is associated with a long winter rest period for larvae, and a short subterranean period (May-July).

The second zone is in the region of the Mediterranean coast, from Tanger to Nador,where the insect lives on artificial pine stands(mostly Pinus halepensis MILL.).

The climatic conditions (mild winters and cool summers) are associated with a chronologically freeer biological cycle .

There is no winter rest period for larvae, which enter their subterranean period between January and March.

The third zone includes artificial Pine stands of eastern Morocco, the southern Rif and the northern High Atlas regions.

Here, conditions are difficult for the insect, because summers are very hot and winters rather cold.

Thus, those three regions clearly exhibit different eco-climatic conditions and different biological cycles.

The authors, comparing climatic demands of the insect and climatic conditions in Morocco, conclude that the insect is not found at present in all its potential distribution area.

Population levels are relatively low, compared to those observed in other Mediterranean countries (Spain, France, Italy, ...), but, from time to time mass outbreaks can be observed.

The authors find that natural enemies, principally egg-parasites (Ooencyrtus pityooampae MERCET, Tetrast-iohus servadei DOM .

and Trichogramma embryphagwn HARTIG), can be an effective bio-tic destruction potential of the insect, particularly in low altitudes.

They studied the geographical distribution of those parasites and their abundance in a few locations over a period of two years.

Only control methods which apply to strictly defined locations can be used in natural forests of Cedar or Pine trees ( chemical or microbiological control).

In artificial Pine stands, mechanical operations can be undertaken if they do not affect natural enemies of the Processionary Caterpillar .Microbiological methods could also be applied by plane but there is little reason for ^heir use at the present time.