Insecticidal effect of some plant extracts on the Alfalfa Weevil Hypera postica (Coleoptera: Curculionidae)
Hemin A Neima and Rebwar A Mustafa
This study was conducted to examine the three types of plant extracts against the Alfalfa weevil Hypera postica under laboratory condition, namely: Neem Azadirachta indica (Meliaceae), Oleander Nerium Oleander (Apacynaceae) and Eucalyptus Eucalyptus camaldulensis (Myrtaceae). Concentrations of 0, 10, 20, and 40 were tested for all plant extracts. Mortality rates for larvae were determined at 2–4 days and for adults at 2-8 days after treatment. This study showed that Neem leaves extract was the most effective, causing 73.33% after 4 days larvae mortality within 4 days and 96.66% adult mortality within 8 days after treatment among all the tested biorationals. Our results suggested that Neem leaves extract insecticide could be applied for H. postica control as an alternative insecticide for chemicals. In general, the toxicity results of all tested plant extracts against all instars and adult phase of H. postica in this research showed a good relationship between mortality percentage and number of days after treatment. The mortality rate increased with number of days for all examined biorationals.