Amblydromalus limonicus: a "new association" predatory mite against an invasive psyllid (Bactericera cockerelli) in New Zealand

The tomato/potato psyllid, Bactericera cockerelli, has been a pest of crops such as potato and tomato in North America for nearly a century and recently invaded some parts of Central America. It invaded New Zealand in May 2006 and is now distributed in both the North and South Island. Before our study, there had been no reports of Amblydromalus limonicus feeding on the tomato/potato psyllid in the US or other areas. After the invasion of the tomato/potato psyllid into New Zealand, we have observed numerous populations of local A. limonicus attacking the tomato/potato psyllid on greenhouse capsicums and tomatoes in the greater Auckland region, providing a certain degree of natural control. In these areas, A. limonicus was common before the invasion of the tomato/potato psyllid. This new association between a local predatory mite and an invasive insect is now well established. A. limonicus cultures have been maintained on capsicums (and sometimes tomato) infested with psyllids in greenhouses for the last three years. Laboratory studies showed that A. limonicus adults could survive and reproduce on the eggs, and first, second, and third instar nymphs of B. cockerelli, as well as on sugar excreted by psyllids, while immature A. limonicus could complete development on the psyllid sugar and first instar nymphs of B. cockerelli. A female predator consumed on average 2.5 psyllid eggs, 2.1 nymph I, 0.5 nymph II, 0.03 nymph III and 1.6 psyllid sugar droplets per day. Given that A. limonicus can be mass-reared and is now commercialized, it offers a new opportunity for the biological control of this psyllid.