Authors:
TAMGNO*, Beranger Raou; NGAMO TINKEU
, Leonard Simon; DJIETO-LORDON
, Champlain and
NGASSOUM
, Martin Benoit ,Cameroon |
Abstract:
In spite of the effectiveness of the essentials oils and flour of leguminous seeds against insect
attacks, they are less attractive to producers that continue to use chemicals that have potential
adverse effects on consumers and the ecosystems through pollution. The present research was
carried out to evaluate insecticidal properties of powdery formulations of essential oils of 3
plants: leaves of Eucalyptus citriodora (Myrtaceae), dried fruits of Xylopia aethiopica (Dunal) A.
Richard (Annonaceae) and the roots of Echinops giganteus var. lelyi C.D Adams (Asteraceae)
with seeds of black bean on Sitophilus oryzae. The toxicity by contact-inhalation of essential
oils, alone or in combination, in different concentrations is evaluated against young adults of S.
oryzae with two weeks old after 24 hours. For powdery formulation, the test of contact-ingestion
and inhalation is evaluated in different doses each week during 7 weeks. The research carried out
reveals that X. aethiopica is the most active on S. oryzae with the lethal doses 50 and 90
respectively 37.1 and 57 ppm. In combination, E. giganteus which alone is not insecticidal,
enhance significantly the insecticidal efficiency of the 2 other essential oils. The most
insecticidal powdery formulation is that of E. citriodora with 100% of mortality two weeks after
the application. The present work gives evidence of the insecticidal efficiency of a powdery
formulation in the protection of stored cereals from weevil attacks. This method potentially has
no adverse effect on consumers and on the environment at the doses used and could be
developed and popularized
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