Semiochemicals: their identification and application in pest control
Paper ID : 1317-3IICE (R1)
Authors:
Brigitte Frérot *
INRA, UMR Iees - 1372. Route de St Cyr F-78000 Versailles
Abstract:
In an insect-plant interaction, plant semiochemicals play an important role in locating host-plants by insects for feeding and oviposition. Here, I will first describe some basic concepts and define some essential terms. Then, major sequential steps involved in semiochemical studies will be expounded upon. The first step in that regard will be designing behavioral bioassays. Behavioral experiments demonstrate if the insect behaviors such as host- and oviposition site-seeking, and mate-finding are olfactory regulated. If it is proven to be true the next step will be extraction of volatile compounds from the source that emanates them and subsequently assestment of the extract in behavioral tests. In case if the behavioral bioassays demonstrate that the insects respond to the extract this indicates that there are most probably a hadfull of bioactive chemicals eliciting such a response. Hence, the extract is subject to chemical identification by gas chromatography coupled with mass spectrometry (GC-MS). Electroantennography (EAG) alone or coupled with GC (GC-EAD) or GC-MS-EAD helps to screen for bioactive chemicals present in the extract that are detected by olfactory sensory neurons housed in the antennal sensilla. The next step is to behaviorally test if a synthetic mixture of all the GC-EAD-active compounds at certain (preferably natural) ratio elicits a behavioral response similar to when the extract was used. Landing behavior should also be studied to design a trap adapted to the insect behavior. The last assessment is to conduct an experiment under natural conditions in the field to assess the proficiency of the trap dispenses and improve the trap catch.
Keywords:
Insect-plant interaction, Behavioral bioassays, Chemical identification Electroantennography.
Status : Paper Accepted (Oral Presentation)