Proteomic investigation of aphid honeydew reveals an unexpected diversity of proteins

in PLoS ONE (2013), Accepted pending revision

Acaricidal activities of Santolina africana and Hertia cheirifolia essential oils against the two-spotted spidermite (Tetranychus urticae)

in Pest Management Science (2012), DOI 10.1002/ps.3269

BACKGROUND: Many plant essential oils show a broad spectrum of activity against pests. This study investigated the effects of two essential oils on Tetranychus urticae, one of the most serious pests in ... [more ▼]

BACKGROUND: Many plant essential oils show a broad spectrum of activity against pests. This study investigated the effects of two essential oils on Tetranychus urticae, one of the most serious pests in the world. RESULTS: The chemical composition of the two oils was characterised by GC-MS. The most abundant component in the Santolina africana (Jord. & Fourr) oil was terpinen-4-ol (54.96%), while thymol (61%) was prevalent in the Hertia cheirifolia (L.) oil. Mortality and fecundity were measured upon treatment with oil concentrations ranging from 0.07 to 6.75 mg L-1 with a Potter spray tower.Mite mortality increased with oil concentration, with LC50 values of 2.35 mg L-1 for S. africana and 3.43mg L-1 for H. cheirifolia respectively. For both oils, a reduction in fecundity was observed at concentrations of 0.07, 0.09 and 0.29mg L-1. Artificial blends of constituents of oils were also prepared and tested with individual constituents missing from the mixture. The results showed that the presence of all constituents was necessary to equal the toxicity of the two natural oils. CONCLUSION: S. africana and H. cheirifolia oils can provide valuable acaricide activitywith significantly lower LC50 values. Thus, these oils cause important mortality and reduce the number of eggs laid by females. [less ▲]

Acaricidal activities of Santolina Africana and Hertia Cheirifolia, two endemic plants of north Africa, on the two spotted spider mite (Tetranychus urticae)

Poster (2011, May)

The two-spotted spider mite, Tetranychus urticae Koch, is a worldwide pest which feeds on a large variety of plant families. Because its resistance to acaricides is spreading rapidly, the development of ... [more ▼]

The two-spotted spider mite, Tetranychus urticae Koch, is a worldwide pest which feeds on a large variety of plant families. Because its resistance to acaricides is spreading rapidly, the development of new biological control tactics for population management is crucial. Plant extracts, such as Santolina africana and Hertia cheirifolia (Asteraceae), may represent viable alternatives, since they are currently considered to be minimumrisk pesticides. Although these two plants are known for their biocidal properties, the extract concentration that provides the most efficient control has not yet been precisely determined. In this study, we conducted a series of laboratory experiments to determine the susceptibility of adult females to different concentrations of S. africana and H. cheirifolia extract. These plants were steam-distilled and sprayed using a Potter spray tower. Mortality and fecundity were measured upon treatment with extract concentrations ranging from 0.07 to 6.75 mg/L. Female mortality increased with concentration, with LD50 values of 2.35 mg/L for S. africana and 3.43 mg/L for H. cheirifolia, respectively Reduced fecundity was previously observed at concentrations of 0.07, 0.09 and 0.29 mg/L .The chemical composition of the two oils were characterised by GC-MS. The most abundant components of the S. africana oil were terpinen-4-ol (44%), α- terpineol (11.31%) and borneol (6.73%). Camphor (15.11%), terpinen-4-ol (14.2%), α- terpineol (9.3%) were characteristic of the Hertia oil. [less ▲]

Assessment of the acaricidal activity of several plant extracts on the phytophagous mite Tetranychus urticae (Tetranychidae) in Tunisian citrus orchards

in Bulletin de la Société Royale Belge d'Entomologie = Bulletin van de Koninklijke Belgische Vereniging voor Entomologie (2011), 147(I-IV), 71-79

To develop sustainable pest control in Tunisian citrus orchards, the present work aimed to evalute the toxicity of 31 plant extracts obtained from Tunisia and two synthetic acaricides (spirodiclofen and ... [more ▼]

To develop sustainable pest control in Tunisian citrus orchards, the present work aimed to evalute the toxicity of 31 plant extracts obtained from Tunisia and two synthetic acaricides (spirodiclofen and fenbutatin oxide) on the phytophagous mite species Tetranychus urticae (Koch). [less ▲]

Contrôle de Tetranychus urticae par les extraits de plantes en vergers d'agrumes

in Entomologie Faunistique = Faunistic Entomology (2011), 63(4), 229-235

Tetranychus urticae est un acarien extrêmement polyphage, reconnu comme un ravageur majeur pour une grande quantité de plantes cultivées. Cet acarien cause d’importants dégâts sur agrumes et ... [more ▼]

Tetranychus urticae est un acarien extrêmement polyphage, reconnu comme un ravageur majeur pour une grande quantité de plantes cultivées. Cet acarien cause d’importants dégâts sur agrumes et principalement sur citronnier, se traduisant par de lourdes pertes économiques. L’objectif de ce travail est de mettre en évidence les propriétés acaricides d'extraits de plantes sur T. urticae. Douze extraits (macérats) issus de 12 plantes et deux acaricides de synthèse (Spirodiclofen et Fenbutatin oxyde) ont été choisis pour les essais en verger de citronniers. Ces résultats montrent que trois macérats extraits d’Allium sativum, A. cepa et Deverra scoparia présentent des propriétés acaricides comparables aux deux acaricides de synthèse qui sont les produits de référence. Cette efficacité perdure jusqu’à plus de 15 jours. Le macérat de D. scoparia a présenté l’activité acaricide la plus toxique et la plus rapide sur la population de T. urticae, 21 jours après traitement par rapport aux autres extraits et par rapport aux produits de référence. Ce travail permettra de mettre en place un programme de lutte intégrée visant le contrôle efficace des tétranyques s’attaquant aux citronniers. Les expériences en verger ont démontré que les extraits végétaux ont un effet acaricide pour T.urticae. [less ▲]

Placenta-Like Structure of the Aphid Endoparasitic Wasp Aphidius ervi: A Strategy of Optimal Resources Acquisition.

in PloS one (2011), 6(4), 18847

Aphidius ervi (Hymenoptera: Braconidae) is an entomophagous parasitoid known to be an effective parasitoid of several aphid species of economic importance. A reduction of its production cost during mass ... [more ▼]

Aphidius ervi (Hymenoptera: Braconidae) is an entomophagous parasitoid known to be an effective parasitoid of several aphid species of economic importance. A reduction of its production cost during mass rearing for inundative release is needed to improve its use in biological control of pests. In these contexts, a careful analysis of its entire development phases within its host is needed. This paper shows that this parasitoid has some characteristics in its embryological development rather complex and different from most other reported insects, which can be phylogenetically very close. First, its yolkless egg allows a high fecundity of the female but force them to hatch from the egg shell rapidly to the host hemocoel. An early cellularisation allowing a rapid differentiation of a serosa membrane seems to confirm this hypothesis. The serosa wraps the developing embryo until the first instar larva stage and invades the host tissues by microvilli projections and form a placenta like structure able to divert host resources and allowing nutrition and respiration of embryo. Such interspecific invasion, at the cellular level, recalls mammal's trophoblasts that anchors maternal uterine wall and underlines the high adaptation of A. ervi to develop in the host body. [less ▲]

Comparative toxicities of a wild Plant essential oil and blends of its major constituents on mortality and fecundity of spider mites (Acari: Tetranychidae)

in Lochynski, Stanislaw; Wawrzenczyk, Czeslaw (Eds.) 41th International Symposium on Essential Oils (ISEI 2010) (2010, September)

Involvement of odorant cues in the process of superparasitism avoidance

Poster (2010, August)

The ability to avoid superparasitism provides a selective advantage to parasitoid females, allowing them to avoid depositing eggs in lower quality host. We observed in a Y-olfactometer that generalist ... [more ▼]

The ability to avoid superparasitism provides a selective advantage to parasitoid females, allowing them to avoid depositing eggs in lower quality host. We observed in a Y-olfactometer that generalist aphid parasitoids, Aphidius ervi and Aphidius rhopalosiphi (Hymenoptera, Braconidae), were more attracted toward non-parasitized than parasitized Sitobion avenae (Hemiptera, Aphididae) colonies. We collected the odors released from healthy aphids and aphids parasitized for 2 and 6 days using an electronic nose. Sitobion avenae alarm pheromone, (E)-ß-farnesene (EßF), was the only chemical identified, and was found in lower quantities in parasitized aphids. Both parasitoid species provided pronounced electrical depolarizations to EßF in electroantennography (EAG), and both were attracted to the latter compound in the Y-olfactometer. Parasitoid attraction was known to be guided by a variety of odorant cues released by plants and hosts, and our results support the hypothesis that the aphid alarm pheromone acts as a kairomone for A. ervi and A. rhopalosiphi. [less ▲]

Isolation, pure culture and characterization of Serratia symbiotica, the R-type of secondary endosymbionts of the black bean aphid Aphis fabae.

in International Journal of Systematic and Evolutionary Microbiology (2010)

An intracellular symbiotic bacterium was isolated from the flora of a natural clone of the black bean aphid Aphis fabae. The strain was able to grow freely in aerobic condition on a rich medium containing ... [more ▼]

An intracellular symbiotic bacterium was isolated from the flora of a natural clone of the black bean aphid Aphis fabae. The strain was able to grow freely in aerobic condition on a rich medium containing 1% of each of following substrates; dextrose, yeast extract and peptone of casein. Pure culture was achieved through the use of solid-phase culture on the same medium and was designated CWBI-2.3T. 16S ribosomal DNA sequence analysis revealed that CWBI-2.3T strain was a member of the gamma-3 subgroup of the class Proteobacteria, having high sequence identity (>99%) with the R-Type of secondary endosymbiont found in several aphid species Serratia symbiotica. As strain CWBI-2.3T (=LMG 25624T =DSM 23270T) was the first R-type symbiont to be isolated and characterized, we proposed to designate it as the type strain of Serratia symbiotica species. [less ▲]

Adsorption of essential oil components of Xylopia aethiopica (Annonaceae) by kaolin from Wak, Adamawa province (Cameroon).

in Applied Clay Science (2009), 44(1-2), 1-6

Essential oils of aromatic plants are nowadays cited as suitable tools for better protection of stored grains from insect pest attacks. These chemical insecticides are less attractive to producers because ... [more ▼]

Essential oils of aromatic plants are nowadays cited as suitable tools for better protection of stored grains from insect pest attacks. These chemical insecticides are less attractive to producers because of their low persistence and difficulty to use as pure product. There is therefore a need to formulate themas an easy handling chemical with better persistence. The present work aimed to study the formulation through adsorption of active components of Xylopia aethiopica Dunal (Annonaceae) essential oil on kaolin. X. aethiopica essential oil was obtained by hydrodistillation in a Clevenger type apparatus unit. Essential oil obtained was analysed by a GC–FID and a GC–MS. The adsorption measurements were performed with collected two kaolin fractions (F1 <100 μm; F2 <50 μm) and two kaolin fractions after H2O2 treatment (F3 <50 μm; F4 <2 μm). The kaolin was characterized by XRD, XRF, FTIR; its specific surface area was determined by the B.E.T method. The amount of essential oil adsorbed was inversely proportional to the particles size. Treatment of kaolin with hydrogen peroxide increased the adsorption capacity of essential oil components. The components adsorbed in highest amounts were sabinene, β-pinene, α-pinene and β-phellandrene. [less ▲]