title: Repellency of Plant Extracts against the Legume Flower Thrips Megalurothrips sjostedti (Thysanoptera: Thripidae).
abstract: Megalurothrips sjostedti Trybom is an important pest of cowpea (Vigna unguiculata L.) in Africa. To propose an alternative to chemical control, the repellency of 24 plant extracts was evaluated against adult female thrips of M. sjostedti in the laboratory. Plant extracts in ethanol were separately applied on a filter paper disk in a still air visual cue olfactometer. The results showed highly significant differences in repellency among extract type, concentration and their interactions. We classified the level of repellency into four categories as strong, good, moderate and weak or non- repellent based on hierarchical ascendant classification. We identified Piper nigrum, Cinnamomum zeylanicum, Cinnamomum cassia as strong repellents. Five extracts were classified as good, eight as moderate and the remaining eight extracts were weak or non-repellent. Repellency of the extracts increased with the concentration suggesting that the behavioral response of M. sjostedti was dose-dependent. Mono- and sesquiterpene hydrocarbon compounds from seven highly repellent extracts were identified by gas chromatography-mass spectrometry (GC/MS). The use of repellent extracts could be useful in developing integrated pest management strategies for thrips on legume crops. In this regard, the specific modes of action of the identified compounds need to be investigated to incorporate them into the existing crop protection strategies.
authors.affiliation: International Centre of Insect Physiology and Ecology (icipe), Nairobi 30772, Kenya. abayleyegn@icipe.org.|Montpellier SupAgro, UMR CBGP CIRAD/INRA/IRD/SupAgro, Campus International de Baillarguet, CS 30016, Montferrier-sur-Lez 34988, France. abayleyegn@icipe.org.|Dipartimento di Agricoltura, Alimentazione e Ambiente (Di3A), University of Catania, Via Santa Sofia 100, Catania 95123, Italy. abayleyegn@icipe.org.
authors.forename: Andnet
authors.initials: A
authors.lastname: Abtew
authors.affiliation: International Centre of Insect Physiology and Ecology (icipe), Nairobi 30772, Kenya. ssubramania@icipe.org.
authors.forename: Sevgan
authors.initials: S
authors.lastname: Subramanian
authors.affiliation: International Centre of Insect Physiology and Ecology (icipe), Nairobi 30772, Kenya. xcheseto@icipe.org.
authors.forename: Xavier
authors.initials: X
authors.lastname: Cheseto
authors.affiliation: Montpellier SupAgro, UMR CBGP CIRAD/INRA/IRD/SupAgro, Campus International de Baillarguet, CS 30016, Montferrier-sur-Lez 34988, France. serge.kreiter@supagro.fr.
authors.forename: Serge
authors.initials: S
authors.lastname: Kreiter
authors.affiliation: Dipartimento di Agricoltura, Alimentazione e Ambiente (Di3A), University of Catania, Via Santa Sofia 100, Catania 95123, Italy. gtgarzia@unict.it.
authors.forename: Giovanna Tropea
authors.initials: GT
authors.lastname: Garzia
authors.affiliation: International Centre of Insect Physiology and Ecology (icipe), Nairobi 30772, Kenya. thibaud.martin@cirad.fr.|Centre de coopération internationale en recherche agronomique pour le dévelopement (CIRAD), UPR HORTSYS, Montpellier F-34398, France. thibaud.martin@cirad.fr.
authors.forename: Thibaud
authors.initials: T
authors.lastname: Martin
keywords: Megalurothrips sjostedti; Olfactometer; Piper nigrum; plant extracts; repellency