Essential Oils composition and toxicity tested by fumigation against Callosobruchus maculatus (Coleoptera: Bruchidae) pest of stored cowpea

Abstract

Insect infestation on stored cowpea (Vigna unguiculata) is an economic obstacle to agriculture. In this context, a test in laboratorial scale was proposed aiming to investigate Ocimum gratissimum, O. basilicum, Cymbopogon nardus, C. citratus, Lippia alba, Mentha arvensis, Schinus terebinthifolius and Cordia verbenacea essential oils (EOs) fumigant potential on control of cowpea-weevil (Callosobruchus maculatus) life cycle. Thus, EOs were extracted and analyzed by GC/MS, furthermore, were used for evaluating mortality, oviposition and new adults emergence. As a result of EOs analyses linalool (32.8%) and eugenol (48.1%) in O. basilicum; eucalyptol (14.8%) and eugenol (74.5%) in O. gratissimum; menthyl acetate (10%) and menthol (73.3%) in M. arvensis; citronellal (50.3%) and nerol (10.8%) in C. nardus; citral (75.8 and 87.1%) in C. citratus and L. alba respectively; α-santalene (35.8%) and β-sinensal (17.7%) in C. verbenacea and α-pinene (23,1%), δ-3-carene (32.1%) and limonene (16.9%) in S. terebinthifolius were reported. In biological tests, EOs showed toxic effect on cowpea-weevil life cycle, inhibiting over 80 and 98% oviposition and new insects emergence, respectively, except for C. verbenacea EO.