Chemical Composition and Insecticidal Activities of Mentha Longifolia and Mentha Mozaffarianii Essential Oils against Callosobruchus Maculatus

Essential oils from two species of Mentha genus, (Mentha longifolia L. and Mentha mozaffarianii Jamzad), from the mint family Lamiaceae that grow in Iran were isolated and analyzed by GC and GC-MS and their insecticidal and repellent activities were investigated against adult cowpea beetles. Mortality rates increased with increasing of the time of exposure and concentration, where M. mozaffarianii oil showed more potent toxicity. Using the topical application, LD۵۰s values of M. mozaffarianii and M. longifolia oils at ۹۶ h after exposure against adults were ۲۲.۷ and ۳۹.۴ μg/adult, respectively. In the fumigant test, LC۵۰s at ۹۶ h after exposure was between ۳۸.۵ and ۵۵.۴ µL/L air against adults, respectively. The results demonstrated that no concentration-dependent effect was observed in the test of the repellent effect and M. longifolia oil was most repellent to C. maculatus adults at ۱۰ µl/l air (۲۹.۰۰%) while M. mozaffarianii oil’s repellency was ۹% at a lower concentration of ۵ µl/l air. The main chemical components of the M. longifolia oil were Pulegone (۴۸.۶۷%), Menthone (۱۴.۳۱%), ۱, ۸- Cineole (۹.۳۷%) and Camphor (۶.۶۰%) while the major constituents of oil of the M. mozaffarianii were Piperitone (۲۳.۵۹%), Linalool (۱۴.۴۴%), ۱, ۸- Cineole (۱۱.۷۷%) and Piperitenone oxide (۹.۳۹%).