Seasonal Occurrence and Vertical Distribution of Euschistus servus (Say) and Euschistus tristigmus (Say) (Hemiptera: Pentatomidae) in Pecan Orchards2

Abstract

Euschistus servus (Say) and E. tristigmus (Say) were monitored near and in pecan orchards at ground level only and in pecan orchards from the ground to the upper canopy. Modified pyramidal traps, baited with Euschistus spp. aggregation pheromone, were placed on the ground along a hedgerow adjacent to a pecan orchard, at the orchard edge, and at the orchard center to monitor seasonal occurrence. Vertical distribution of E. servus and E. tristigmus was monitored by placing pheromone-baited traps at preselected heights. Traps on the ground along the hedgerow, orchard edge, and orchard center captured similar numbers of stink bugs each month from May through September, with an increase in October at all locations (combined data for both species). Single traps placed at different heights captured peak numbers of E. servus in early and late season; whereas, traps captured peak numbers of E. tristigmus during the late season. More E. servus were captured in traps on the ground than in traps in the canopy, but more E. tristigmus were captured in the canopy at 9 m. With two baited traps placed at different heights at the same tree, more E. servus were captured on the ground than in the lower or upper canopy, but most E. tristigmus were captured in the lower and upper canopy than on the ground. Placement of traps on the ground or at 9 m resulted in more captures of E. servus on the ground and more captures of E. tristigmus at 9 m. Although E. servus and E. tristigmus were captured both on the ground and in the pecan canopy, numbers of captured E. servus and E. tristigmus were affected by trap height. Thus, sampling Euschistus species in pecan, and possibly other arboreal habitats, should be done throughout the canopy.