Spatial heterogeneity of stink bug (Hemiptera: Pentatomidae) populations in agricultural systems

Abstract

Knowledge on spatial patterns of insect pest populations and the ecological processes influencing these patterns can be directly applied to the management of pests in agricultural systems. Recent increases in stink bug populations, importantly the invasive Halyomorpha halys (Stål 1855), has caused unprecedented economic losses in the mid-Atlantic United States. To inform integrated pest management programs, I quantified the spatial heterogeneity of stink bug population density in field crops at multiple spatial scales (field edge, entire fields and regional), and identified the associated environmental factors and the underlying ecological mechanisms (i.e. climatic tolerances, resource quality and availability).

At corn and soybean field edges, highest density of stink bugs was limited to the first few crop rows. At some study sites, fields adjacent to woods and buildings harbored higher density of stink bugs than those adjacent to open areas. Injury to corn kernel damage, and soybean pod and seed increased with stink bug density, and was highest at the field edges. Stink bug density was also positively associated with yield loss in soybean.

In entire fields of corn-soybean, H. halys was found in very low density or absent beyond 25m from the field edge. At study sites with high stink bug populations, interpolated density values showed potential dispersal of H. halys, particularly adults and large nymphs, from corn into soybean, coinciding with the end of dough stage in corn and beginning of soybean seed development stage.

Temperature and developed areas, and proportion of forest and crop areas were important predictors of regional patterns in H. halys and Chinavis hilaris abundance, respectively. For Euschistus servus, temperature and forest cover influenced patterns at broad spatial scale. Adjacent habitat influence, with highest abundance along woods, on stink bug density was limited to within field scale, and difference in abundance between sites was driven primarily by temperature gradient.

These results directly inform field level stink bug management strategies through planting date and orientation of fields in the landscape, and for timing and intensity of treatments, as well as area-wide management. This research also identified roles of temperature and landscape in facilitating or impeding invasive pest populations.