Abstract
Phagostimulants for the larvae of the onion fly, Hylemya antiqua MEIGEN were isolated from onion bulbs. Among the basic, acid and neutral fractions of the methanolic extract, only the neutral fraction showed phagostimulatory activity. This fraction contained glucose, fructose and sucrose at 0.09 M, 0.07 M, and 0.06 M, respectively. Fructose and sucrose were effective at 0.1 M, but glucose was not effective at any concentration. The mixture of these sugars at 0.05 M each was also effective. Fructose and sucrose in onion bulbs were determined to act as phagostimulants additively to the larvae of the onion fly, suggesting the importance of the fructose moiety.
