BIO-INSECTICIDAL EFFECT OF POLYPHENOL EXTRACTS OF ANVILLEA RADIATA AGAINST CEREAL APHID RHOPALOSIPHUM PADI

To reduce the abusive apply of artificial organic pesticides with discernment, biodegradable bio-pesticides origin from plants were used as an alternative phytosanitary method against crop pests. This experimentation allowed testing in vitro the bio-insecticidal activity of Anvillea radiata Coss and Dur (Asteraceae), endemic plant from the southeastern Algeria, against the cereal aphid Rhopalosiphum padi (Linnaeus, 1758). Three concentrations were tested (D1= 5mg/ml, D2= 2.5mg/ml and D3= 1.25mg/ml) with the butanolic and chloroformic extracts. The results showed a mortality rate of R. padi varying significantly by treatment and concentration according to the tested substances. The quantitative analysis of the two extracts shows that the crude butanolic extract is rich in polyphenols (348.935±7.456 μg EAG/mg MS) compared to the crude chloroformic extract (56.754±0.982 μg EAG/mg MS). Samely to the insecticidal effect tested, the concentration of 5 mg/ml presented an important insecticidal activity with the butanolic extract (62%) higher than the chloroformic extract (26%). Also, the lethal doses (LC50) of the crude butanolic extract were estimated by 23.07 mg/ml, 6.71 mg/ml and 5.70 mg/ml respectively after 24, 48 and 72hours of the treatment

AGRO-MORPHOLOGICAL RESPONSE OF CORN (Zea mays L.) TO A BIOSTIMULANT FROM THE SOUTHEASTERN ALGERIA

Abstract: This study highlights the effect of a biostimulant based on Trichoderma, indigenous antagonistic fungus from the region of Touggourt, on the development of a local variety of corn. This study was conducted at the experimental station of National Institute of Agronomic Research (Sidi Mehdi, Touggourt) as a complete randomaize block designe. The examined agro-morphological parameters showed that the application of this bioproduct stimulates vegetative growth of the plant. Besides, better germination and earliness of seeds. The results showed more interesting values were obtained in the treated plots (height = 135.9 cm, diameter = 28.9 mm, surface of leaves = 318 cm2, Pan = 10.2 panicles/plant) compared to those of the controls (height = 98.6 cm, diameter = 23.7 mm, surface of leaves = 260.4 cm², Pan = 7.4 panicles/plant). Statistical analyzes confirmed the existence of a very highly significant difference between treated and control subjects

Repellency and toxicity of the crude ethanolic extract of Limoniastrum guyonianum against Tribolium castaneum. Acheuk, F., Belaid, M., Lakhdari, W., Abdellaoui, K., Dehliz, A., and Mokrane, K. (Algeria/Tunisia)

In nature, the interaction between plants and insects has led to the production of a set of secondary compounds. Many plant secondary metabolites have significant insecticidal activity. The aim of this study is to evaluate the repellent and insecticidal effect of the crude ethanolic extract of Limoniastrum guyonianum against adults of the red flour beetle Tribolium castaneum. For the insecticidal activity, five doses (100, 200, 400, 600, and 800 µg/insect) were tested and were topically applied onto insect thorax. An area preference method was adopted to assess the repellent activity. A phytochemical study and measurement of two enzymatic biomarkers: acetylcholinesterase (AChE) and gluthatione Stransferase (GST) were made to understand the mechanisms of toxic action of the tested extract. Phytochemical study showed the presence of various groups of natural products. The plant is rich in flavonoids, tannins, alkaloids, and glycosides. Low amount of saponins was noted. The study also showed that this plant does not contain iridoids. For repellent activity, the results showed that the highest dose (800 µg/insect) exhibited obvious repellent effect against T. castaneum. The repellency percentage was 90.14 ± 2.5% after 4 h of exposure. The crude extract was found to be toxic to T. castaneum and the corresponding LD50value was 218.3 μg/insect. Moreover, the extract inhibits the activity of the acetylcholinesterase (IC50: 205.7 µg/insect)

Chemical composition and biological properties of Cotula cinerea essential oil from Sahara of Algeria

International audienceThe work focuses on the valorization of the plant Cotula cinerea Del., which grows spontaneously in Algeria. It is collected from two stations in the province of El Oued, to assess the chemical composition of essential oils, from two different zones whereas Beni Guecha is a reg unlike Sidi Aoun is a sandy area characterized by the presence of dunes, and to test biological activities. Oil analysis by CG/MS enabled the identification of 28 terpene components representing 96.94% ± 2.35 of the total oil. The analyzed samples differ significantly in their chemical composition. Dominated by high levels of oxygenated monoterpenes (78% and 41%), the oils are rich in 1.8-cineole, camphor, trans-thujone, cis-chrysanthenol and terpinen-4-ol. Firstly, the antibacterial potential of C. cinerea essential oils showed good inhibition against E. coli ATCC25922 and Staphylococcus aureus ATCC25923 with an inhibitory diameter ranging from (16.70–14.64 mm). In addition, the results of the antioxidant effect of these oils showed that they have moderately weaker antioxidant power than ascorbic acid. On the other hand, these EOs showed significant antifungal potential against the two fungi tested