Activité insecticide d’une souche marocaine de Bacillus thuringiensis sur la mouche méditerranéenne : Ceratitis capitata (Wied.) (Diptera : Tephritidae)

Le présent travail consiste à étudier l’effet de deux types de toxines (δ -endotoxines et β -exotoxines) extraites à partir d’une souche de Bacillus thuringiensis (Bt A9) isolée d’un sol au Maroc sur la mouche Ceratitis capitata Wied (Diptera ; Tephritidae). les endotoxines de Bt A9 agissent sur la mortalité des larves et la longévité des adultes. par contre, les exotoxines présentent un effet notamment sur l’émergence des adultes. Les résultats de cette étude montrent que la souche Bt A9 présente une activité insecticide importante sur C. capitata. Les toxines de cette souche pourraient être utilisées dans la lutte biologique de cet insecte ravageur de plusieurs cultures fruitières au Maroc.Mots-clés : Bacillus thuringiensis, activité insecticide, ceratitis capitata,endotoxines, exotoxines

Analysis of two larval-pupal parasitoids (Hymenoptera, Braconidae) in the biological control of Ceratitis capitata (Wiedemann) in Spanish Mediterranean areas

The Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), is considered a key pest in fresh fruit and citrus production in the Mediterranean Bassin. Nowadays, it is being studied the use of several ecological methods against this pest in some Mediterranean countries (Spain, Morocco and Tunisia), like the Sterile Insect Technique (SIT), the classical biological control (CBC) and the search for native parasitoids. Two exotic larval-pupal parasitoids of fruit-flies have been imported by the IVIA to Spain: Diachasmimorpha tryoni and D. longicaudata. As it occurs in other countries, in Spain it is being studied the combined use of the SIT and overflooding releases of parasitoids to combat Medfiy populations. To achieve this, only one parasitoid species is usually mass reared and released. Over the last two years we have been analyzing the competitiveness of D. longicaudata and D. tryoni in order to choose the species to be used together with the SIT for the integrated control of the Medfl

Preliminary assessment of insecticidal activity of Moroccan actinobacteria isolates against mediterranean fruit fly (Ceratitis capitata)

Microbial insecticides are considered as the most sustainable and ecologically acceptable means of crop protection. Here we report the ability of some Moroccan actinobacteria isolates to produce larvicidal compounds against the Medfly (Ceratitis capitata Wied.). Thus, actinobacteria isolates were tested for their insecticidal activity through biological and chemical screening. The primary biological screening using the brine shrimp bioassay showed that 12 isolates out of 210 (5.71%) have been found to be highly toxic at the concentration of 100 µg mL-1. Among these, isolates OS46, 37 and B62 were the most toxic with an LC50 of 0.26, 0.34 and 0.84 µg mL-1, respectively. The freeze-dried fermentation of the selected isolates showed moderate to high insecticidal activity against the first instar larvae of C. capitata, and the most important pupation reduction was obtained for isolates 37 and B89 (0 and 6% of pupation, respectively). The chemical screening on thin layer chromatography of the crude extract of the most important isolates using specific insecticide family’s reagents showed a variety of compounds depending on isolate with at least one active spot for each tested specific reagent. Finally, the inhibition of acetylcholinesterase activity test was carried out in order to assess the possible nature of insecticidal activity of selected isolates. The obtained results show that, except the isolate 37 which probably acts by a different mode of action, all other isolates were active. This finding could have an applicative value for the potentiality of utilizing Moroccan actinobacteria isolates as an alternative to chemical insecticides in pest management mainly against C. capitata. Key words: Moroccan actinobacteria, insecticidal activity, biological screening, chemical screening, <i>Ceratitis capitata</i&gt

Composition chimique et activités antioxydante et antimicrobienne de l'Huile essentielles extraite de Thymus satureioides

International audienc

Chemical composition and antibacterial activity of <i>Lavandula coronopifolia</i> essential oil against antibiotic-resistant bacteria

<div><p>The aim of this study was to analyse the composition of the essential oil (EO) of <i>Lavandula coronopifolia</i> from Morocco and to evaluate its <i>in vitro</i> antibacterial activity against antibiotic-resistant bacteria isolated from clinical infections. The antimicrobial activity was assessed by a broth micro-well dilution method using multiresistant clinical isolates of 11 pathogenic bacteria: <i>Klebsiella pneumoniae</i> subsp. <i>pneumoniae</i>, <i>Klebsiella ornithinolytica</i>, <i>Escherichia coli</i>, <i>Enterobacter cloacae</i>, <i>Enterobacter aerogenes</i>, <i>Providencia rettgeri</i>, <i>Citrobacter freundii</i>, <i>Hafnia alvei</i>, Salmonella spp., <i>Acinetobacter baumannii</i> and methicillin-resistant <i>Staphylococcus aureus</i>. The main compounds of the oil were carvacrol (48.9%), <i>E</i>-caryophyllene (10.8%) and caryophyllene oxide (7.7%). The oil showed activity against all tested strains with minimal inhibitory concentration (MIC) values ranging between 1% and 4%. For most of the strains, the MIC value was equivalent to the minimal bactericidal concentration value, indicating a clear bactericidal effect of <i>L. coronopifolia</i> EO.</p></div