The objective of this study was to evaluate the phytochemical, antimicrobial, and insecticidal properties of tannins derived from Cydonia oblonga fruit.Qualitative and quantitative methods were used for the determination of the phytochemicals of Cydonia oblonga fruits. The tannins of this fruit were extracted using solvents and salts, and their antimicrobial activity against S. aureus ATCC 25923 and E.coli ATCC 25322 and C.albicans was investigated.The lethal effect of tannins extract was evaluated on Tribolium confusum under controlled laboratory conditions (at temperature 28 ± 2°C, relative humidity 75 ± 5%, and photoperiod of 16:8).The obtained results showed very interesting levels of tannins extraction (9.66%, 7.33%) using solvents and salts, respectively. The obtained tannins exerted no antimicrobial activity for the tested strains.On the other hand, all doses (50 μl, 100 μl, and 200 μl) of tannins tested on Tribolium confusum adults by the inhalation method showed a bioinsecticidal effect with an LD50 of 109.64 μl of tannin extract. Cydonia oblonga fruit can be an alternative for the development of natural drugs and insecticides with an important role in the fight against parasites.

Dynamics of the populations of Phyllocnistis citrella Stainton (1856) and impact of its parasitic complex in Algeria.

This study was conducted to evaluate the insecticidal activity of the endophytic fungus Isaria fumosorosea Wize isolated from Ricinus communis L. against Locusta migratoria L. and Acanthoscelides obtectus Say. To evaluate the insecticidal activity, a mixture of fungal extract and spore suspensions (1x107, 1x106 and 1x105 spores/ml of dissolved extract) were applied against the insects. It was found that I. fumosorosea had a good insecticidal activity, positively proportional to concentration and time after exposure (24, 48, 72 hours). A maximum mortality rate of 80% for A. obtectus and 70% for L. migratoria at 1x107 spores/ml of dissolved extract was recorded. Preliminary phytochemical analyses of the fungal extract revealed the presence of alkaloids, flavonoids and phenols. Additionally, a fungal development on the insects bodies has also been noticed; that is undoubtedly explained the recorded insecticidal activity.

Abstract:The study has for objective the determination of the efficiency of the aqueous extracts from seeds of Peganum harmala L. on the mortality of the larvas of 5th stage and on the fertility of the female adults of Locusta migratoria cinerascens. For that purpose, a breeding of lo custs was realized in th e conditions of labor atories. At hatching, the larvae are fed daily basis lawn Stenotaphrum americanum and a pro tein supplement of wheat b ran. The extraction of the aqueous extract of the seeds of P. harmala is done after maceration in the ethanol, under magnetic stirring using a rotavapor. To determine larval mortality L5, two modes of treatment have been made, one by contact and another by ingestion, using for bo th treatment 4 doses in a g eometric progression, 0.03 mg/mL, 0.06 mg/mL, 0.12 mg/mL and 24 mg/mL. Th e results showed that the mortality for the doses of 0 .12 mg/mL and 0.24 mg/mL, reaches respectively 40% and 60% on the 3rd day, as well for the treatment by contact as by ingestion. But the LD50 for ingestion treatment is lower. It is 0.19 mg/mL contrary to that of the contact treatment (0.19 mg/mL). The larvae that survived the treatment by ingestion, have suffered morphological changes as well as physiological which consist of a deformation of the wings, delayed of the larval molt, of 6 day s, b locking the fledg ing, the ch ange of the pigmentatio n as well as an extension of the preoviposition. Fertility was a lso affected and females lay only twice, a small number of eggs, unlike untreated females which come to lay 3 times with an average of 62.7 eggs/female at first spawning against 50 eggs for the females treated.

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