The processionary caterpillar of the pine lepidopteran, Thaumetopoidae is the most formidable defoliator of conifers in the Mediterranean basin. This species is in phase of permanent extension to attack in addition to the pine forests to the various stands of the cedar of the Atlas. The current study, which is part of the various investigations aimed at protecting cedar groves against this defoliator, focuses on the evaluation of an aerial control campaign that was conducted in 2007 in the cedar grove of Theniet El-Had. The main results obtained show that : * The degree of defoliation of...