ABSTRACT
Plutella xylostella (L.) is responsible for considerable vegetable crop losses in the metropolitan region of Manaus, Brazil. In recent decades, essential oils have been investigated as an alternative to synthetic insecticides. The genusPiperis widely distributed in Amazonia and essential oils from these plants have insecticidal properties. This study describes the chemical composition of the essential oils fromPiper capiterianumandPiper krukoffiias well as the lethal and sublethal effects onP. xylostella. The phytotoxicity of the oils on the host plant was also evaluated. Globulol was the major constituent of theP. krukoffiioil ando-cymene was the major constituent of theP. capitarianumoil. The oil fromP. capiterianumexhibited greater toxicity to larvae and eggs. This oil also presented greater repellant action, feeding deterrence and mild phytotoxicity to the host plant (Brassicae oleraceae). The findings suggest that this oil can be used in the preparation of a formulated insecticide for the management ofP. xylostellain different development phases. However, further studies are needed to evaluate the effect of this oil on crops under field conditions as well as non-target organisms and determine the cost-benefit ratio of a product formulated withP. capitarianumoil.
Subject(s)
Insecticides , Oils, Volatile , Animals , Brazil , Insecticides/chemistry , Insecticides/toxicity , Larva , Oils, Volatile/chemistry , Oils, Volatile/toxicity , Plant Oils/toxicityABSTRACT
Essential oils from leaves of Ocotea limae and Ocotea gardneri species were analyzed by GC-FID and GC-MS. The analysis revealed the presence of 48 components accounting for 98.1 ± 1.3% e 98.0 ± 0.5% of the essential oils from the O. limae and O. gardneri, respectively. The oils were characterized by high percentage of sesquiterpenes. The mains compounds identified in the essential oils were spathulenol (13.3 ± 0.5%), ß-caryophyllene (12.4 ± 0.5%), bicyclogermacrene (11.3 ± 0.4%) and germacrene D (10.9 ± 0.3%) from the O. limae and germacrene D (26.9 ± 0.9%) e bicyclogermacrene (21.7 ± 0.7%) from the O. glomerata.
Los aceites esenciales de hojas de Ocotea limae y Ocotea gardneri fueron analizados por GC-FID y GC-MS. El anaÌlisis reveloÌ la presencia de 48 componentes que representan 98,1 ± 1,3% y 98,0 ± 0,5% de los aceites esenciales de O. limae y O. gardneri, respectivamente. Los aceites se caracterizaron por un alto porcentaje de sesquiterpenos. Los principales compuestos identificados en los aceites esenciales fueron espatulenol (13,3 ± 0,5%), ß-cariofileno (12,4 ± 0,5%), biciclogermacreno (11,3 ± 0,4%) y germacreno D (10,9 ± 0,3%) de O. limae y germacreno D (26,9 ± 0,9%) y bicyclogermacreno (21,7 ± 0,7%) de la O. glomerata.
