Preventive, curative and persistent activities of Lantana camara and Psidium guajava essential oils against Prostephanus truncatus (Horn)

Abstract

Within the framework of the search for alternative methods of struggle against the destruction of the maize by P. truncatus (Horn), the vegetable kingdom, in particular the aromatic plant, now offers enough possibilities. The essential oils extracted from these vegetable materials could constitute a credible alternative because less expensive and without major impact on the human health, the animals and on the environment. The present work concerns the bioactivity of the volatile extracts of two aromatic plants known in rural areas in Benin for the preservation of the agricultural products. The chemical compositions of essential oils extracted from L. camara and P. guajava leaves were studied by gas chromatography coupled with the mass spectrometry (GC/MS). Forty-eight compounds were identified representing 96.8% of the L. camara leaves essential oil from Abomey-calavi. The main compounds (> 5%) are: β-caryophyllene (19.3%), sabinene (15.9%), (Z)- β-ocimene (11.2%), α-humulene (6.5%), germacrene-A (5.8%). The essential oil extracted from P. guajava leaves collected to Banigbe (Benin) contained fifty-one compounds corresponding to 97.7% of the total weight of the volatile extract. The major compounds (> 5%) of this essential oil are epi-β-bisabolol: 11.7%; β-caryophyllene: 10.9%; β- bisabolene: 7.5%. The different tests realized on local variety of the maize grain (Zea mays) "Massahouekoun" showed that these essential oils variously have shown larvicidal and ovicidal effects on larvae and eggs of P. truncatus adult. These activities caused a significant delay in the development of young P. truncatus due to the doses applied and also the active compounds of the essential oils studied.