ALLELOCHEMICAL ACTIVITY IN ARDISIA SPECIES (MYRSINACEAE) AGAINST SELECTED ARTHROPODS

Significant differences were found among 4 species of Ardisia (Myrsina ceac) when evaluated as host plants in separate tests for oviposition and longevity by the twospotted spider mite, Tetranychus urticae Koch, and for nymphal development by the whiteflies Bemisia argentifolii Be llows & Perring and the greenhouse whitefly Trialeurodes vaporariorum (Westwood). After being confined for 48 h on leaf disks, the number of T. urticae alive did not differ among the different Ardisia species b ut the number of eggs laid on A, crenata Sims and on A, japonica (Horn stead) Blume was significantly lower than on the other species. T. urt icae females remained alive an average of 2.8 d on A. crenata leaf dis ks, 5.0 d on A. japonica and A, escallonioides Schechtendal & Chamisso , and 9.4 d on A. crispa (Thunberg) Aphonse De Candolle. T. urticae la id significantly fewer eggs on A, crenata, A. japonica, and A. escallo nioides than on A. crispa. Nymphal mortality of B. argentifolii and T. vaporariorum was significantly higher on leaves attached to plants of A. crenata and A. japonica than A. escallonioides. Development rate o f Ist and 2nd instars of the fall armyworm, Spodoptera frugiperda (Smi th), was not significantly influenced when fed a meridic diet treated with pulverized dry leaf residue of either A. crenata or A. japonica. Development rate, larval weight, and cumulative mortality of the latte r instars were significantly affected by high-concentrations of A. jap onica. A purified major leaf component from A. crenata was isolated us ing high-pressure liquid chromatography with ultraviolet detection and found to be highly soluble in water. Oviposition by T, urticae female s placed on disks cut from excised eggplant, Solanum melongena L., lea ves that had imbibed an aqueous concentration of the purified leaf com ponent was significantly reduced with increasing concentrations of the leaf component.