Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 28, 2000
Publication Date: N/A
Interpretive Summary: Some plant-feeding species of stink bugs such as Euschistus servus and E. tristigmus are serious pests of pecan and result in economic losses to pecan growers not only through crop damage but through control costs. We determined the seasonal occurrence of these two pest stink bug species in pecan by baiting traps with a stink bug aggregation pheromone. Trapping stink bugs in this manner may lead to better stink bug control strategies which reduce damage and costs to the grower. It was also determined that populations of the two stink bug species studied were not evenly distributed vertically in the pecan orchard. Adult Euschistus servus were more abundant on the ground and in the lower canopy, whereas adult E. tristigmus were more abundant in the upper canopy of pecan. This provides information concerning the propensity for differential damage to pecan by the two species and gives insight about the effectiveness of alternative stink bug control practices for each species when manipulation of orchard floor cover crops is involved.
Technical Abstract: Euschistus servus and E. tristigmus 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 caught 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 E. Tristigmus traps captured peak numbers during the late season. More E. servus were captured throughout the season on the ground than at 3, 6, 9, or 12 m during the two years this study was done. In contrast, more E. tristigmus were captured at 9 m during both years. Even when two baited traps were placed at different heights at the same tree, significantly more E. servus were caught on the ground than in the lower or upper canopy but more E. tristigmus were captured in the lower and upper canopy than on the ground although the difference was not significant. Placement of traps on the ground and 9 m resulted in more captures of E. servus on the ground, whereas more E. tristigmus were captured 9 m. Our results show that in pecan, E. servus and E. tristigmus respond differentially to the same aggregation pheromone at different heights.