Optimum site selection for blacklight insect traps as predicted by relating tobacco hornworm collections to factors describing trap surroundings

Seventy parameters describing surroundings of 51 blacklight insect trap locations on St. Croix, U. S. Virgin Islands were related to insect categories of male, mated female, virgin female, total tobacco hornworm (Manduca sexta), and the white belly (M. sexta harterti). Data were obtained from an on-site survey pertaining to slope of land at trap site, deviation of slopes from prevailing wind, roadways, incident light, slope to obstruction, and distance from traps to obstructions. Obtained from descriptive data of locations were trap density, distance from shorelines, elevation above sea level, slope of land in vicinity of traps, deviation of slope in vicinity of traps from prevailing wind, land-use category, vegetation type, geology type, groundwater potential yield, groundwater chloride, soil limitations to agriculture or development, soil association, and soil capability class.

Significance of relationships between insect collections and criteria was determined by analysis of variance for 14 discrete factors, and by correlation and multiple regression analyses for the continuous factors. Criteria significantly related to collections five or more times were type of obstruction, slope to obstruction, distance to obstruction, distance to shoreline, soil limitations to agriculture and development, slope of trap site, slope of trap vicinity, and deviation of slope in vicinity of traps from prevailing wind.

Significant one to four times were vegetation type, geology type, soil association, distance to roadway, related traffic flow on roadway, weighted obstruction, percent obstruction, land-use category scaled according to estimated ability to support an insect population, slope deviation at site from prevailing wind, groundwater potential yield, soil capability class, relative ultraviolet radiation of incident light, relative intensity of incident light, elevation of trap site, and trap density.