30 research outputs found
Electrophysiological and behavioral characterization of bioactive compounds of the Thymus vulgaris, Cymbopogon winterianus, Cuminum cyminum and Cinnamomum zeylanicum essential oils against Anopheles gambiae and prospects for their use as bednet treatments
Exploring the Kairomone-based foraging behaviour of natural enemies to enhance biological control
Kairomones are chemical signals that mediate interspecific interactions beneficial to
organisms that detect the cues. These attractants can be individual compounds or
mixtures of herbivore-induced plant volatiles (HIPVs) or herbivore chemicals such as
pheromones, i.e., chemicals mediating intraspecific communication between herbivores.
Natural enemies eavesdrop on kairomones during their foraging behaviour, i.e., location
of oviposition sites and feeding resources in nature. Kairomone mixtures are likely
to elicit stronger olfactory responses in natural enemies than single kairomones.
Kairomone-based lures are used to enhance biological control strategies via the
attraction and retention of natural enemies to reduce insect pest populations and
crop damage in an environmentally friendly way. In this review, we focus on ways to
improve the efficiency of kairomone use in crop fields. First, we highlight kairomone
sources in tri-trophic systems and discuss how these attractants are used by natural
enemies searching for hosts or prey. Then we summarise examples of field application
of kairomones (pheromones vs. HIPVs) in recruiting natural enemies. We highlight the
need for future field studies to focus on the application of kairomone blends rather
than single kairomones which currently dominate the literature on field attractants for
natural enemies. We further discuss ways for improving kairomone use through attract
and reward technique, olfactory associative learning, and optimisation of kairomone lure
formulations. Finally, we discuss why the effectiveness of kairomone use for enhancing
biological control strategies should move from demonstration of increase in the number
of attracted natural enemies, to reducing pest populations and crop damage below
economic threshold levels and increasing crop yield.The French National Research Agency (ANR) through CIRAD; the University of Pretoria; the National Research Foundation and the German Academic Exchange Service (DAAD) In-Region Postgraduate Scholarship.http://www.frontiersin.org/Ecology_and_Evolutionam2022Zoology and Entomolog
Lemon terpenes influence behavior of the African citrus triozid Trioza erytreae (Hemiptera: Triozidae)
The African citrus triozid, Trioza erytreae Del Guercio (Hemiptera: Triozidae) is one of the primary vectors of the bacterium Candidatus Liberibacter spp. which causes citrus greening, a disease of global economic importance in citrus production. Despite its economic importance, little is known about its chemical ecology. Here, we used behavioral assays and chemical analysis to study the chemical basis of interaction between T. erytreae and one of its preferred host plants, Citrus jambhiri. In dual choice Y-tube olfactometer assays, lemon leaf odors attracted females but not males compared to plain air or solvent controls. However, in a petri dish arena assay, both sexes were arrested by lemon leaf odors. Coupled gas chromatography-mass spectrometry (GC/MS) analysis revealed quantitative differences in the odors of flushing and mature leaves, dominated by terpenes. Twenty-six terpenes were identified and quantified. In Petri dish arena assays, synthetic blends of the most abundant terpenes mimicking lemon flushing leaf odors elicited varying behavioral responses from both sexes of T. erytreae. A nine-component blend and a blend of the three most abundant terpenes; limonene, sabinene and β-ocimene arrested both sexes of T. erytreae. In contrast, a six-component blend lacking in these three components elicited an avoidance response in both sexes. Furthermore, both sexes of T. erytreae preferred the three-component synthetic blend to lemon crude volatile extract. These results suggest that lemon terpenes might be used in the management of T. erytreae