IN-VITRO ANTIMICROBIAL AND NEMATOCIDAL ACTIVITY OF ACETOGENINS IDENTIFIED FROM EXOCRINE SECRETIONS OF STEPHANITIS AND CORYTHUCHA LACE BUG NYMPHS (HETEROPTERA, TINGIDAE)

Lace bug nymphs of the genera Corythucha and Stephanitis have secretor y setae with microdroplets distributed over their body (including ante nnae), from which novel acetogenins have been identified. Selected lac e bug acetogenins, synthetic analogs, and synthetic compounds of plant origin were evaluated for biological activity against common microorg anisms and the parasitic nematode Ascaris suum (L.). Ten of the 12 lac e bug-derived and related synthetic compounds tested were active in a disk diffusion test that challenged 9 bacteria and 9 fungal pathogens; of the 10 compounds causing zone inhibition, 6 were active against 3 or more species of bacteria. Zone inhibition occurred against only gra m-positive bacteria which included Bacillus subtilis (Ehrenvberg) Cohn , Clavibacter michiganense subspecies michiganese (Smith) Davis, Gilla spie, Vidaver & Harris, Rhodococcus facians (Tilford) Goodfellow, Acti nomyces bovis Harz, A. naeslundi Thompson & Lovestedt, and Corynebacte rium diphtheriae (Kruse) Lehmann and Neumann. Activity against gram-ne gative bacteria was minimal. In a 2nd test with only gram-positive org anisms, the bacteria C. michiganense, R. facians, and C. diphtheriae p roduced the largest zones. There was no inhibition of growth by 4 spec ies of plant fungi and 5 insect fungal pathogens. Two compounds stunte d growth of A. suum larvae with growth inhibition similar to that caus ed by anthelmintic standards.