Cereals constitute a relevant part of human and domestic
animal diet. Under storage conditions, one of the most
significant problems of these crops is insect pests as the
maize weevil (
Sitophilus zeamais
Motschulsky). This
insect species is usually controlled by means of synthetic
insecticides but problems as toxic residues and resistance
has led to the search for more friendly control alternatives
such as botanical insecticides. The aim of this research was
to evaluate, under laboratory conditions, the insecticidal
properties of the powder and the essential oil of peumo
(
Cryptocarya alba
[Molina] Looser; Lauraceae) leaves
against
S. zeamais. The variables assessed were toxicity
by contact and fumigant activity, adult emergence (F
1),
repellent effect, and impact on wheat (
Triticum aestivum
L.)
seed germination. A completely randomized design was used
with five treatments and 10 replicates. The higher mortality
levels were obtained at 80 g powder kg
-1 grain and 40 mL
essential oil kg
-1 grain of
C. alba; in both cases, the mortality
of adult
S. zeamais surpassed 80%. The emergence of adults
S. zeamais (F1) was reduced by 100% at 80 g powder kg
-1
grain and 40 mL essential oil kg
-1 grain. Germination of
wheat seeds treated with
C. alba powder and essential oil
was not affected. Both, the powder and the oil treatments
showed repellent effect, but not fumigant activity.
