Monitoring stink bug density in pecans to predict percentage nut damage

Arkansas pecan grower surveys indicated a priority to develop a standardized stink bug sampling method and a scientifically-based economic threshold for a pest management program to reduce stink bug damage to pecan nuts. The brown stink bug, Euschistus servus (Say), has been the most prevalent stink bug collected in Arkansas pecans. Previously, researchers sampled only the lower pecan canopy for stink bugs. As a result, no one has assessed either stink bug densities on nuts or percentage nut damage in pecan trees at different canopy heights. Therefore, a 15 m boom cherry picker was used in this study to assess nut damage and estimate stink bug densities at the lower, middle and upper portions of the pecan tree in seven Arkansas pecan groves. Stink bug densities were estimated biweekly from pecan nut water stage to harvest using four monitoring techniques: 1) yellow pyramid traps baited with Euschistus spp. aggregation pheromone; 2) visually or binocular-assisted counts of stink bugs on 20 nut clusters per pecan tree, 3) water spray by pressure washer or air blast sprayer to knock down stink bugs to ground cloth; and 4) UV trap in lower canopy. A regression is being calculated of percentage stink bug damage to corresponding estimated stink bug densities throughout pecan trees in several groves. Progress is being made in developing an economic threshold for stink bugs in pecan.