Compatibility of the nymphal parasitoid, Tamarixia radiata, with an 'attract and kill' strategy for controlling Asian citrus psyllid on residential citrus

The South Texas citrus industry must content with the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), spreading huanglongbing (HLB) among residential citrus and from residential neighborhoods into nearby groves.  Effective psyllid control is essential for reducing HLB spread but conventional insecticidal treatment of psyllid-infested dooryard citrus trees is unsustainable.  The nymphal parasitoid, Tamarixia radiata Waterston (Hymenoptera: Eulophidae), is aggressively released as a biocontrol agent for D. citri in South Texas but currently provides insufficient control because parasitism rates are highly variable and impact on psyllid populations is low when nymphs are scarce.  Environment-friendly control strategies that target adult psyllids should complement D. citri suppression by T. radiata.   Our strategy uses an 'attract-and-kill' (AK) device that specifically lures and kills D. citri adults.  This device exploits the color-preference of D. citri and is beta-cyfluthrin-infused to quickly kill adults upon contact.  From March 2019 to March 2020, we compared D. citri populations and nymph parasitism among lemon trees baited with 20 AK devices per tree and non-baited lemon trees in residential blocks near citrus groves in the Rio Grande Valley.  During this study, infestations of D. citri adults and nymphs on AK-baited trees were respectively 66% and 78% lower than on non-baited trees.  Baiting lemon trees did not negatively affect T. radiata because parasitism of nymphs on AK-baited trees was proportionately similar or higher than on non-baited trees.  Our findings show that these AK devices are highly effective and compatible with T. radiata for D. citri suppression on residential citrus.