PHYTOCHEMICALS AND BIOLOGICAL ACTIVITY OF PLANT EXTRACTIVES AGAINST THE COTTON LEAFWORM Spodoptera littoralis (Boisd.)

Abstract

Out of eleven ethanolic plant extracts (Carnm carvi, Cassia fistula, Lantana camara, Yucca spp., Ambrosia maritime, Pluchea dioscoridis, Tipuana tipu, Zizyphus spind-christi, Artemisia herba-alba, Cassia nodosa and Lawsonia inermis ) tested for their toxicity against the 4th larval instar of cotton leafwonn by residual thin film technique, two extracts showed higher mortality percentages, which were_ • Carnm carvi and Cassia fistula . Their LC50 were 0.438 and 0.541 mg/cm2 · respectively.

Testing the feeding detergency of plant extracts showed that Ambrosia maritima extract gave the lowest SC50 value of 0.076 mg/cm2, while Cassia nodosa gave the highest SC 50 1.363 mg/cm2 .

The preliminary phytochemical studies showed the existence of different chemical groups.

The biological studies of Carnm carvi indicated that the chlorofmm fraction (Fch) was of the most effective fraction (LC50 0.252 mg/cm2) followed by hexane fraction (Fh) and the crude extract. While after exposure of the three fractions to iodine, iodide chloroform fraction (Fchl) (LC50 0.189 mg/cm2) was the most effective one followed by (Fhl).

Studying the residual effect of 3 mg/cm2 of (Fch) and (Fchl) indicated that the (Fchl) had high residual effect it was still 100% after 11 days and reached 56.6% after 56 days of exposure.

Phytochemical studies were held on chlorofmm fraction of caraway._ The identification of this fraction (Fch) showed that carvone was the dominant compound 36.86%, followed by linoleic acid 24.13% and ethyl linoleate 13.02%. In addition to five monoterpenes, phytol isomer and sesquiterpenes. esquiterpenes.