DIURNAL EMISSION OF VOLATILE COMPOUNDS BY JAPANESE BEETLE-DAMAGED GRAPE LEAVES

The volatile compounds liberated by Japanese beetle (Popillia japonica Newman) feeding on grape leaves (Vitis labrusca L.) were studied. Ten consecutive collections of 3 hr duration were performed on live vines starting at 09:00 and continuing until 15:00 the following day. Relea se of most compounds followed a diurnal pattern, with the period of pe ak emission from 12:00 to 15:00 and the period of least emission from 00:00 to 03:00. Nineteen compounds were identified from the beetle-dam aged vines, most of which were aliphatic aldehydes, alcohols and ester s as well as terpene hydrocarbons. During periods of peak emission, vo latile production from beetle-damaged vines was about 50-times higher than that of undamaged vines. (C) 1997 Elsevier Science Ltd. All right s reserved.