A new bioassay for determining the susceptibility of onion (Allium cepa) bulbs to onion thrips, Thrips tabaci (Thysanoptera: Thripidae)

摘要

Abstract A series of experiments was conducted to develop a bioassay for determining the susceptibility of Allium plants to adult female onion thrips. Onion thrips (Thrips tabaci (Thysanoptera: Thripidae)) are the main insect pest on onions in New Zealand. This research aimed to develop better methods for determining the susceptibility of Allium species leaves and onion bulbs to onion thrips. Discs, 10mm diam., cut from leek (Allium porrum) and onion (Allium cepa) leaves or onion bulbs, were put singly into small plastic Petri dishes with 1‐day‐old adult female thrips, and kept at 25oC in 16 hlight: 8h dark. After 3 days the discs were stained in acid fuchsin and the eggs counted using a stereo microscope with transmitted light. Adult thrips survived equally well on leek leaves and onion bulb scale, but laid more eggs per day on onion leaves than on leek leaves and least on onion bulbs. Thrips laid fewer eggs per day when there was more than one thrips per dish. Changing discs daily or leaving them f...