Biosurveillance for an invasive pest of maize, Prostephanus truncatus, across North America and in Greece

Authors: QUELLHORST, HANNAH - Kansas State University; SAKKA, MARIA - University Of Thessaly; ODJO, SYLVANUS - International Maize & Wheat Improvement Center (CIMMYT); Ludwick, Dalton; BINGHAM, GEORGINA - University Of Nebraska; Roeder, Karl; Hesler, Louis; Hanley, Raina; Zhu, Junwei; WILKINS, RACHEL - Kansas Department Of Agriculture; Ponce Jr, Marco; ATHANASSIOU, CHRISTOS - University Of Thessaly; ZHU, KUN YAN - Kansas State University; Gerken, Alison; Morrison Iii, William

Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/28/2025
Publication Date: 9/8/2025
Citation: Quellhorst, H.E., Sakka, M.K., Odjo, S., Ludwick, D.C., Bingham, G.V., Roeder, K.A., Hesler, L.S., Hanley, R.M., Zhu, J.J., Wilkins, R.V., Ponce Jr, M.A., Athanassiou, C.G., Zhu, K., Gerken, A.R., Morrison Iii, W.R. 2025. Biosurveillance for an invasive pest of maize, Prostephanus truncatus, across North America and in Greece. Journal of Applied Entomology. https://doi.org/10.1111/jen.70016.
DOI: https://doi.org/10.1111/jen.70016

Interpretive Summary: Biosecurity protocols to prevent the introduction of invasive pests are an increasingly important aspect of pest management in a globalized economy. Grain and grain-based commodities are especially vulnerable to damage by invasive insects because they are transported in bulk and infestations may be difficult to detect. The larger grain borer is a major pest of stored maize and a known biosecurity threat to the USA. Although not yet introduced into the USA, its range is expected to expand and it is important to monitor for the presence of this insect around where maize and wheat are grown and stored. For this study, we monitored larger grain borer activity and activity of closely related beetle species at >10 sites ranging from Mexico to North Dakota and Greece to evaluate how latitude, habitat, and season impacted the population levels of these insects. In total, we captured 2,528 insects in 2021 and 29,080 insects in 2022. Larger grain borer was only documented in Mexico, but in high abundance in both years. Interestingly, it was caught most often in unmanaged and row crop habitats compared to food facilities. A close relative of the larger grain borer, the horned powder post beetle, was caught in row crops and near food facilities at all trapping sites in North America and Greece and abundances were higher in 2022. By contrast, weevils were most often caught near food facilities in all sites. Overall, our results suggest that surveillance efforts for larger grain borer should include field sites where wheat and maize is grown to ensure it is detected early to prevent establishment.

Technical Abstract: Biosecurity is an increasingly important aspect of management of commodities in a globalized economy. The larger grain borer, Prostephanus truncatus, is a known biosecurity threat to the USA, and has been classified as a species-of-concern. Under climate change, P. truncatus is expected to expand its range into the USA from Mexico. In this study, we performed a two-year latitudinal biosurveillance program for P. truncatus, related bostrichids such as P. punctatus, and Sitophilus spp. as key species in and around maize and wheat production at 10–15 sites from 20–47° latitude in North America and Greece to evaluate how habitat, latitude, and season affected spatiotemporal dynamics of these insects. Two types of traps, a 4-funnel Lindgren traps and pitfall traps, were deployed in many of the sites and baited with each species’ pheromones. In total, we captured 2,528 insects in 2021 and 29,080 insects in 2022. Prostephanus truncatus was only documented in Mexico, but in high abundance in both years. Interestingly, even though P. truncatus is a good flier, the funnel trap was equally effective as the pitfall trap in monitoring P. truncatus at sites where it was present. Conspecifics were found most often in natural and row crop habitats in both years compared to food facilities. While captures of P. punctatus were low in 2021, captures of P. punctatus in 2022 most often occurred in natural habitats, but they were still present at row crops and near food facilities. By contrast, Sitophilus spp. were most associated with food facilities. Overall, this study helps inform current risk from P. truncatus, and fundamental patterns of spatiotemporal distribution for several related key stored product insects.