Résumé:
Evaluation of insecticidal effect of two formulated essential oils (Thymus pallescens Noé
and Artemisia herba alba Asso) on Sitophilus granarius (L.) (Coleoptera: Curculionidae)
and Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae).
Cereal grains are the principal human food resource. Insects are the main biological
for their deterioration in storage sites. Our objective is to study the insecticidal potency
of Thymus pallescens Noé and Artemisia herba alba Asso by contact and ingestion, against
Sitophilus granarius (L.) and Rhyzopertha dominica (F.).The resultats of this study show
that the essential oils possess remarquable insecticidal effects on both species
and this proportional to the dos and time. The activity of thyme on Rhyzopertha dominica
by contact varies between 53.33% and 66.67% and from 16.67 to 98.33% by ingestion.
In addition, Artemisia oil recorded a mortality rate of 57.63% to 96.67 per contact and 26.67
to 63.33% per ingestion. On the other hand, the effect of thyme by contact effect
with Sitophilus granarius indicated mortality varies from 61.67% to 83.33% by contact
and from 18.33% to 60% by ingestion. Artemisia oil caused 63.33% to 100% mortality
from contact and 15% to 60% by ingestion from the lowest dose to the highest dose.
For this purpose, the dose D3 corresponds to 20000ppm, shows the greatest efficiency
and with a short exposure time. Thyme oils and Artemisia show greater efficacy by contact
than by ingestion. Including thyme, reported an LD50 of 8392.661ppm for Rhyzopertha
dominica and 7392.014ppm for Sitophilus granarius, for Artemisia oil, LD50 of 9246.012ppm
were obtained for Rhyzopertha dominica and 8508,433ppm for Sitophilus granarius.
