Estimating efficacy and plume reach of different traps and attractants on the capture of Trogoderma granarium Everts

Authors: AGRAFIOTI, PARASKEVI - University Of Thessaly; Morrison Iii, William; DOMINGUE, MICHAEL - Animal And Plant Health Inspection Service (APHIS); LAMPIRI, EVAGELIA - University Of Thessaly; MYERS, SCOTT - Animal And Plant Health Inspection Service (APHIS); ATHANASSIOU, CHRISTOS - University Of Thessaly

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: The khapra beetle is a considered a serious quarantine pest of stored grains in the United States that can infest more than 100 different stored grains and finished food products. There have been an increasing number of interceptions of khapra beetle at ports in the last two decades. However, the current standard trap for khapra beetle may not be fully optimized for the species. In the current study, we evaluated the efficacy of several different trap designs for monitoring khapra beetle populations in an experimental warehouse, including the wall trap, which is the trap that is routinely used for khapra beetle, a modified wall trap that contains a strip of rough tape added to a ladder to help the beetles climb into the trap and a Dome, which is routinely used for monitoring walking stored product insects. The Dome trap outperformed the other two traps for capture of both adult and immature life stages, including the wall trap. In a second experiment, we evaluated the plume reach of the pheromone and food odors that are used as baits for these traps individually and in combination, to determine the distance at which odors can attract beetles. When used in a trap previously described by our group (termed the Wilkins trap), plume reach was relatively small, and a trap drew individuals from 296 square feet, but trap catches declined significantly when insects were released >3 feet from the trap. Overall, the most effective trap was the Dome trap, while the short plume reach of the baits used in traps was identified as an important factor that strongly influences trapping efficacy for this insect species. Our results are important for improving the efficacy of surveillance programs for khapra beetle.

Technical Abstract: The khapra beetle is a serious pest of stored grains that infests more than 100 different commodities. In the current study, three bioassays were carried out. In bioassay I, Dome, Wall and Modified Wall traps were evaluated in four rooms. In bioassay II, Dome, Wall, Modified Wall and Wilkins traps were examined in two rooms. For both bioassays, traps were checked once a week and Trogoderma granarium were counted. In Bioassaay III, the Wilkins trap was used with different attractants in each room (wheat germ, pheromone, or pheromone + wheat germ) and T. granarium were deployed at different release points (0.1, 0.5, 1.0 and 1.9 m) in each cardinal direction from the trap. Traps were checked every three days and alive individuals were kept in vials with soft wheat for progeny production after 65 d. RESULTS: Based on our results, in bioassay I, Dome traps collected significantly more individuals compared to the other traps. In bioassay II, Modified Wall and Wilkins traps significantly collected the fewer individuals compared to the Dome trap. In bioassay III, the highest number of individuals was captured at 0.1 m, and we found plume reach of Wilkins interception traps to be 2.62–5.71 cm, while trapping area was 10.1–27.5 m2. Regarding the progeny production, the highest number of individuals was found from the release distance of 0.1 m. CONCLUSIONS: The most effective trap was the Dome trap. The distance from the trap/attractant source is an important parameter that can affect trapping efficacy.