Host-Finding Responses of Onion and Seedcorn Flies 1 to Healthy and Decomposing Onions and Several Synthetic Constituents of Onion 2

Publisher Website
Google Scholar
Abstract
Decomposing onion seedlings and bulbing plants elicited a greater host-finding response by female (but not male) onion flies, Hylemya antiqua (Meigen), than did healthy plants. Clear acetate cone traps baited with the onion chemical, n-dipropyl disulfide, caught more female and male onion flies than traps baited with plants or propanethiol. Of variously damaged onions, only mechanically injured plants released a significant male response, whereas female onion flies were caught by traps baited with maggot infested, Fusarium inoculated, and mechanically injured hosts. Seed corn fly, H. platura (Meigen), females showed a slight, but statistically significant, preference for rotting onion plants, rotting seedlings and healthy seedlings. These results suggest that distinctive blends of host plant volatiles, differing quantitatively or qualitatively, release varying degrees of female and male onion fly host-finding behavior. The apparent advantage of female preference for the decomposing onion would be increased larval survival due to easier larval penetration of onion bulbs and faster larval development.