Assessment of the Insecticidal Potential of the Eupatorium buniifolium Essential Oil Against Triatoma infestans (Hemiptera: Reduviidae). A Chiral Recognition Approach

GUERREIRO, A C; CECATI, F M; ARDANÁZ, C E; DONADEL, O J; TONN, C E; SOSA, M E

NEOTROPICAL ENTOMOLOGY

ENTOMOLOGICAL SOC BRASIL

Año: 2018

1519-566X

In this research, bioactivities toward the Chagas? disease vectorTriatoma infestans (Klug) (Hemiptera: Reduviidae) by the essentialoil (EO) of Eupatorium buniifolium H. et A. (Asteraceae) are reported.The tests were designed in order to determine ovicidal activity aswell as the response to vapor exposure (fumigant) and to topicalapplication (contact toxicity) and as repellent. In the last three bioassays,nymphs from the 3rd and 4th instar were used. The assayedmaterials were obtained from aerial parts of plants collected duringthe months of March and December, throughout 4 years, in twolocations. The EO samples were subjected to a qualitative analysisby GC-MS and the relative area of each component was reportedby GC-FID. The main monoterpene detected was α-pinene and byusing a chiral column through GC-MS experiments and having bothstereoisomers as standards, we were able to determine that theenantiomer present was S,S-(−)-α-pinene. Although usually in studiesof EOs changes in chemical composition are often observed due tothe time of collection and the environment where the plant develops,in our case the differences were, with some exception, only atthe level of the minor components. The best results were obtained inthe experiments to determine ovicidal activity, fumigant action, andrepellency. No worthy response was found as insecticide in the trialsdesigned for contact toxicity. The results of the studied bioactivitieswere independent of the location, month, and year of collection ofthe plant material. This behavior provides an interesting scope inrelation to the potential use of this natural blend for the control ofthis insect at the nymph stage as repellent as well as for decreasingthe population by ovicidal effect. Notably, in the course of the twochoicerepellency test, it was possible to demonstrate recognition ofone of the enantiomers of the α-pinene, giving rise to a non-commonchirality/response effect. In this assay, the levorotatory isomer wasthe most active as repellent. Considering the abundance of the wildplant under study and the fact that its EO is easy to obtain, it issuggested that it could be an adequate natural resource to controlthis vector in a sustainable way as a complementary approach toconventional methods.