Abstract
The olfactory responses of the larvae of the onion fly, Hylemya antiqua MEIGEN were investigated using thirty-three volatile compounds commonly found in plants and three sulfur compounds. Both first and third instar larvae of the onion fly responded to five alcohols : from propanol to heptanol, three aldehydes : from pentanal to heptanal, three fatty acids : from valeric acid to heptylic acid, twenty-one esters and three green leaf volatiles. The larvae of the onion fly may also make use of aliphatic alcohols, aldehydes, acids and esters other than sulfur compounds as the cues for host finding. To sulfur compounds, first instar larvae strongly responded but third instar larvae did not. The difference in larval food (artificial diet or onion bulbs) was not considered the reason for these diverse responses.
