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Brasília, Brazil

Banguela-Castillo A.,Institute Investigaciones en Fruticultura Tropical IIFT | Ramos-Gonzalez P.L.,Institute Investigaciones en Fruticultura Tropical IIFT | Pena-Marey M.,Institute Investigaciones en Fruticultura Tropical IIFT | Tanaka F.A.O.,University of Sao Paulo | And 3 more authors.
Crop Protection | Year: 2015

Muscodor is an endophytic fungal genus whose members produce volatile organic compounds (VOCs) with broad antimicrobial, nematocidal and insecticidal activities. This study describes the isolation and characterization of a new strain of Muscodor albus, designated as M. albus aa3, from wild pineapple (Ananas ananassoides) plants collected in Havana, Cuba. In vitro cultures of M. albus aa3 on both potato dextrose agar media (PDA) and paddy produced VOCs with antimicrobial activity against Escherichia coli and plant pathogens, including several species of the Phytophthora genus and the wood rot fungus Fomitiporia maxonii; but innocuous to the beneficial mycopathogen Trichoderma koningii. GC/MS analysis indicated the unique composition of the mixture of VOCs emitted by aa3, in which sesquiterpenes represent the most abundant compounds. VOCs emitted during the growth of M. albus aa3 on paddy grains protected Persian lime (Citrus×. latifolia Tanaka) fruits from infection by Phytophthora nicotianae Breda de Haan, suggesting the potential use of this fungus for postharvest biofumigation. Isolation of M. albus from wild pineapple points out this plant as a susceptible host to be colonized by distinct species of the Muscodor genus. © 2015. Source

Werdin Gonzalez J.O.,National University of the South | Werdin Gonzalez J.O.,CONICET | Laumann R.A.,Laboratorio Of Semioquimicos | da Silveira S.,Laboratorio Of Semioquimicos | And 3 more authors.
Chemosphere | Year: 2013

The essential oils from leaves of Schinus molle var. areira, Aloysia citriodora, Origanum vulgare and Thymus vulgaris have showed potential as phytoinsecticides against the green stink bug, Nezara viridula. In this work were evaluated their toxicological and behavioral effects on the parasitoid Trissolcus basalis, a biological control agent of this pest insect. Essential oils were obtained via hydrodestillation from fresh leaves. Insecticide activity in T. basalis females was evaluated in direct contact and fumigation bioassays. Behavioral effects were evaluated in olfactometer bioassays. To evaluate the residual toxicity, females of the parasitoids were exposed to oil residues; in these insects, the sublethal effects were evaluated (potential parasitism and survivorship of immature stages). The essential oils from O. vulgare and T. vulgaris proved to be highly selective when used as fumigant and did not change parasitoid behavior. After one week, the residues of these oils were harmless and did not show sublethal effects against T. basalis. According with these results, essential oils have potential applications for the integrated management of N. viridula. © 2013. Source

Ferreira Santos de Aquino M.,Laboratorio Of Semioquimicos | Ferreira Santos de Aquino M.,University of Brasilia | Dias A.M.,Laboratorio Of Semioquimicos | Borges M.,Laboratorio Of Semioquimicos | And 2 more authors.
Entomologia Experimentalis et Applicata | Year: 2012

Insect parasitoids use a variety of chemical and physical cues when foraging for hosts and food. Parasitoids can learn cues that lead them to the hosts, thus contributing to better foraging. One of the cues that influence host-searching behaviour could be colour. In this study, we investigated the ability of females of the parasitoid wasps Telenomus podisi Ashmead and Trissolcus basalis Wollaston (both Hymenoptera: Scelionidae) to respond to colours and to associate the presence of hosts - eggs of Euschistus heros (Fabricius) (Hemiptera: Pentatomidae) - with coloured substrates after training (associative learning). Two sets of experiments were conducted: in one the innate preference for substrate colours was examined, in the other associative learning of substrate colour and host presence was tested in multiple-choice and dual-choice experiments. In the associative learning experiments, Te. podisi and Tr. basalis were trained to respond to differently coloured substrates containing hosts in two sessions of 2 h each, with 1-h intervals. In multiple-choice experiments, the wasps displayed innate preference for yellow substrates over green, brown, black, or white ones. Even after being trained on substrates of different colours, both parasitoids continued to show preference for yellow substrates. The response to the colours of substrates of both parasitoids was related with the orientation to the plant foliage during the search for hosts. © 2012 The Netherlands Entomological Society. Source

Magalhaes D.M.,Laboratorio Of Semioquimicos | Magalhaes D.M.,University of Brasilia | Borges M.,Laboratorio Of Semioquimicos | Laumann R.A.,Laboratorio Of Semioquimicos | And 4 more authors.
Journal of Chemical Ecology | Year: 2016

Previous studies have shown that the boll weevil, Anthonomus grandis, is attracted to constitutive and conspecific herbivore-induced cotton volatiles, preferring the blend emitted by cotton at the reproductive over the vegetative stage. Moreover, this preference was paralleled by the release of the acyclic homoterpenes (tetranorterpenes) (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT) in Delta Opal cotton being higher at the vegetative than at the reproductive stage. Here, we evaluated whether this difference in release of acyclic homoterpenes also occurred in other cotton varieties, and if boll weevils could recognize these compounds as indicators of a specific cotton phenological stage. Results showed that cotton genotypes CNPA TB-90, BRS-293 and Delta Opal all produced higher levels of DMNT and TMTT at the vegetative stage than at the reproductive stage and that these homoterpenes allowed for principal component analysis separation of volatiles produced by the two phenological stages. Electroantennograms confirmed boll weevil antennal responses to DMNT and TMTT. Behavioral assays, using Y-tube olfactometers, showed that adding synthetic homoterpenes to reproductive cotton volatiles (mimicking cotton at the vegetative stage in terms of homoterpene levels) resulted in reduced attraction to boll weevils compared to that to unmodified reproductive cotton. Weevils showed no preference when given a choice between plants at the vegetative stage and the vegetative stage-mimicked plant. Altogether, the results show that DMNT and TMTT are used by boll weevils to distinguish between cotton phenological stages. © 2016 Springer Science+Business Media New York Source

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