RESPONSE OF AEDES-TRISERIATUS LARVAE TO FATTY-ACIDS OF CLADOPHORA

The activity of a methanol extract residue from Cladophora glomerata against larvae of Aedes triseriatus is confirmed. Fractionation of this residue by solubility in solvents of varying polarity is monitored by bioassay with A. triseriatus larvae. The presence of fatty acids in the active hexane soluble fraction and saponified material obtained therefrom is indicated by1H NMR and IR. The identification of the individual fatty acids is achieved by co-injection and mass GLC of their methyl esters. Saturated and unsaturated fatty acids are screened against larvae and the LD50 values of the most active acids are determined. The LD50 of capric [10:0], lauric [12:0], myristic [14:0] and palmitoleic [16:1 (9 c)] are 14,7, 4 and 3ppm respectively. The most active acids 12:0, 14:0 and 16:1 (9 c) are present in all the fractions examined and are released to water by the powdered alga at pH 8.5. © 1979 Plenum Publishing Corporation.