Non-random host preference by cabbage aphids in canola

In Australia, canola (Brassica napus Linneaus) is the third largest field crop, and it is mainly grown as a rain-fed winter annual crop between April-November. Of the three aphid species [green peach aphids (Myzus persicae Sulzer), turnip aphids (Lipaphis erysimi Kaltenbach), and cabbage aphids (Brevicoryne brassicae Linnaeus) infesting canola in Australia, cabbage aphids cause the most damage to late-season canola crops. Cabbage aphids in Australia are not considered major vectors of plant pathogenic viruses and timing of infestations largely determines their economic impact. Thus, effective management of cabbage aphids requires in-depth understanding of their host preference, as such knowledge can be used to optimize sampling and detection of emerging pest populations. We present novel results from no-choice and multi-choice experiments and provide support for a hypothesis about non-random host preference by cabbage aphids.