The confused flour beetle,
Tribolium confusum
Jaquelin Du Val, 1868, is a common pest insect known for attacking and
infesting stored flour and grain. Biodegradable and ecologically natural products such as essential oils are emerging
candidates for replacement of usually applied chemical pesticides. This work reported the chemical composition and effects
caused by young and mature leaves essential oils (EOs) from
Eucalyptus globulus
Labill. against
T. confusum. For both
oils, no significant differences between yields were observed, being 1,8-cineole the main common constituent. Mature
leaves extracts were rich in oxygenated mono- and sesquiterpenes, whereas young leaves showed greater content of nonoxygenated
compounds. Bioassay was performed using EOs and 1,8-cineole solutions at different concentrations and time
intervals. Adult mortality increased according to concentration and exposure time; young leaves extracts exhibited the
greater effectiveness, highest mortalities (31.67%) at the minor time (2 h). At the lowest concentrations, 1,8-cineole solutions
and mature leaves EOs did not achieve 100% mortality even when the bioassay was concluded (12 h), while at major doses
no insects were alive. These results suggested that young and mature EOs from
E. globulus constitute an alternative natural
product to the control of
T. confusum, since young leaves extracts, rich in monoterpene and sesquiterpene hydrocarbons,
may be potential eligible candidates considering their noticeable insecticidal effects at low applied concentrations and short
times of exposure.
