Bioactivity Impact of Essential Oils Allium sativum L. and Citrus reticulata L. Against Stored Product Insects Tribolium castaneum (Herbst) and Rhyzopertha dominica (F.) تاثيرالنشاط الحيوي للزيوت الأساسية أليوم ساتيفم و سيترس ريتکيول ضد حشرات المنتجات المخزنة ترايبوليم کاستنيوم و ريزوبيرثا دومينکا

Abstract

This study was conducted to estimate the impact of contact and fumigation toxicity of garlic(Allium sativum L.)and mandarin (Citrus reticulata L.) essential oilsagainst two of stored product insects Tribolium castaneum (Herbst) and Rhyzopertha dominica(F.) for 1, 2 and 3 days after exposure under laboratory conditions. Results showed that garlic was more effective than mandarin, where contact LC50 after 3d was 0.336 mg/mL compared to 5.49 mg/mL for mandarin on T. castaneum (Herbst) and0.343 mg/mL, 4.130 mg/mL on R. dominica (F.) at the same investigation period. The same trend was observed for fumigation where LC50 of garlicwere 0.789, 0.386 µL /L airagainst T. castaneum (Herbst) and R. dominica (F.) respectivelyand 7.778, 6.305 µL/L air of mandarin against T. castaneum (Herbst)and R. dominica (F.) after 3days respectively. Gas chromatography-mass spectrometry (GC-MS) analysis showed that the major compounds of garlic essential oil were diallyl sulfide (9.5%), diallyl disulfide (27.9%),dimethyl tetrasulfide (2.9%), allyl methyl trisulfide (17.7%), and diallyl trisulfide (16.8%). In mandarin the main components were tricarbonyl [methyl 6-vinylidenehepta 2,4-dien-1-oate]iron (52.8 %), dimethyl hexane ( 15.28%), p-cymene (5.45 %), limonene (3.88 %) and Ɣ terpinene (9.47 %). The results elucidated that, essential oils may be a promising safe alternatives to synthetic chemical insecticides for control stored product insects either by contact or fumigation treatment and compatible with integrated pest management.