Evaluation Of The Insecticidal Effects Of Extracts And Extracts Fractions Of Nicotiana tabaccum (Solanaceae) And Carica papaya (Caricaceae) On Termites Of The Genus Nasutitermes, Main Pests Of Cocoa Trees In Côte D'ivoire.

[摘要] With a view finding alternative to chemical control, respectful of the environment and effectiveagainst harmful termites, the insecticidal properties of extracts and extracts fractions from the powder oftobacco leaves and seeds of papaya were tested on termite workers of the genus Nasutitermes. The extractswere obtained by maceration and liquid-liquid extraction. In the laboratory, termite workers, collected atNational Center of floristic, were exposed to the extracts in order to assess their effectiveness on themortality of the latter. Each test was performed with 50 individual termites and repeated four times. Thetests were compared to the blank control. Biological tests were carried out on termites with extractsconcentrated for 100 and 200 mg/l. All extracts obtained from tobacco leaves were proved to be veryeffective against termites with maximum mortality in less than 8 hours for aqueous extract. The LC50obtained with the other tobacco leaf extracts were very low (1,2 to 3,4 mg/l) add depending of solventused. As for the extracts obtained from papaya seeds, except hexane extract which gave satisfactory resultsat concentration of 100 mg/l, other extracts did not show any efficacy on termite mortality. Nevertheless,the aqueous and DCM extracts of this powder show efficacy at a high concentration. The LC50 of hexaneextract is between 8,8 and 9,6 mg/l taking into account the studied concentrations. Chemical compoundssuch as alkaloids, sterols and terpenes, saponins and tannins which are in these extracts would beresponsible for insecticidal activity of these extracts.

[学科分类] 工程和技术（综合）

[关键词] insecticidal plants;allelochemicals;pest termites;laboratory test.