SOME CHEMICAL BASES FOR GYPSY-MOTH, LYMANTRIA-DISPAR, LARVAL REJECTION OF GREEN ASH, FRAXINUS-PENNSYLVANICA, FOLIAGE AS FOOD

Green ash is one of the few tree species rejected as food by larvae of the generalist gypsy moth, Lymantria dispar L. (Lepidoptera: Lymantri idae). Such rejection is based especially on chemicals present in gree n ash foliage. The gypsy moth larval feeding-inhibitory activity is co ntained in the ethyl acetate extractables of green ash foliage. Three representative column-chromatographed fractions of the extractables co ntained antifeedant activity. Individual fractions showed weaker antif eedant activity compared to the total ethyl acetate extractables. Acid hydrolysis of the extractables destroyed antifeedant activity and yie lded feeding stimulant activity at higher concentrations. The aqueous extractables were not feeding-inhibitory. Compounds in the green ash e xtractables were separated by TLC, HPLC, CC, and GC.