Black flies are nuisance pests as adults, yet they are best managed in the larval stage in flowing waters. As a result, more effort is put into understanding the distribution of the immature life stages than the blood-seeking females that form nuisance. The seemingly localized nature of Simulium jenningsi Malloch (Diptera: Simuliidae) pest problems in western Maryland offered a study system to investigate the spatial and environmental correlates to their severity. Collections of adult black flies were taken at 260 sites within a 2,000 km2 region centered on Washington County, Maryland, during June, July, and August of 2 yr. Average S. jenningsi counts were greater in the June of both years compared to July and August. Although S. jenningsi was found at the majority of sampling sites, higher fly counts were significantly clustered in the southern portion of the county where the majority of resident complaints originated. A generalized linear mixed-model (GLMM) approach was used to determine the correlates to S. jenningsi abundance. The highest performing model showed a negative relationship of S. jenningsi counts with the amount of surrounding impervious surface, distance to the riffles along the confluence of the Shenandoah and Potomac Rivers, distance to the closest body of flowing water, and light intensity, as well as a positive relationship with elevation and air temperature. The results suggest S. jenningsi females are not readily found in urban environments in this study region, and the most relevant monitoring locations for S. jenningsi may be outside of human population centers.

Abstract Current management practices of nuisance black flies are conducted on an area-wide level and rely on the support of the public to implement programs. In Maryland, a vocal group of residents campaigned their representatives to begin a management program for the black fly Simulium jenningsi Malloch. To determine how residents in Maryland and its surrounding states perceived the severity of black fly nuisance, we deployed surveys online and in-person on the ways their outdoor activities were impacted and the preventive methods used to mitigate nuisance. Online respondents, those with children, and those who had lived in the region for a shorter amount of time were more likely to report black flies as ‘extremely annoying’. Quality-of-life concerns stemming from black fly swarms were primarily related to avoiding outdoor exercise and recreation. The majority of respondents used at least one method of personal protection against black fly annoyance, but satisfaction with any method was low. Methods used by respondents included the removal of standing water and rotting vegetation from their properties, indicating a lack of knowledge about black fly breeding habitats. The results contextualized the needs of residents in future management and topics for outreach efforts to address misconceptions about black fly biology. This study offers an example of the application of social science methodology in understanding the needs of stakeholders in area-wide pest management.