Characterizing brown marmorated stink bug, Halyomorpha halys Stål, host plant usage and acceptability: Methodological strengths and shortcomings

We assessed the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), seasonal patterns of host use and/or preference using three diverse approaches. We compared H. halys captures in small pyramid traps baited with H. halys aggregation pheromone and deployed them in the mid-canopy of individual host trees during discrete intervals over two seasons. Whereas captures were greatest in the late season, there was no significant effect of host tree species on captures, with the presence of pheromone lures likely confounding the results. Harmonic radar was used to measure the retention duration of tagged H. halys on potted trees, including Ailanthus altissima (Mill.) Swingle (Simaroubaceae), Robinia pseudoacacia L. (Fabaceae), Celtis occidentalis L. (Cannabaceae), Morus rubra L. Moraceae, Prunus persica (L.) Batsch (Rosaceae), and Malus domestica Mill. (Rosaceae) as a proxy for host acceptability. Season-long, adults were retained significantly longer on P. persica and pheromone-baited M. domestica (positive control) compared with the non-host grass treatment (negative control). For nymphs, significantly longer retention was recorded on nearly all hosts compared with the non-host grass treatment. We also evaluated the results of molecular gut content analysis of adults collected in the early and late seasons. Plant DNA from 22 genera across 18 families was detected. Commonly detected early-season hosts included Betula, Diospyros, Juglans, Liriodendron, Prunus, Rubus, and Sisymbrium and late-season hosts included Ailanthus, Chenopodium, Juglans, Persicaria, and Prunus. Overall, harmonic radar provided context for seasonal changes in host acceptability, and gut content results provided confirmation of specific host usage at different points in the season. Combining these two methods could provide a more comprehensive approach for defining host use patterns of this polyphagous pest.