Motivating State Workers with Entomology

Abstract

In the early 1980s, my lab group was trying to determine how Spodoptera exigua (Hubner), the beet armyworm, migrated into California. At that time, the belief was that the insect migrated from northern Mexico, or perhaps from Texas (the apparent source of many of California’s problems). To document how this might be occurring, we examined pheromone trap catches of adults and related these to wind patterns and temperatures at elevations up to several thousand feet (as measured by weather balloons released twice daily from a series of military bases). This part of the study was pretty straightforward: the insects not only overwintered in southern California, but were active throughout the year and were migrating in large numbers, even when weather patterns would not facilitate movement from the south (Trumble and Baker 1984). Unfortunately we couldn’t blame Texas for this particular problem—these pests were homegrown. More troublesome was the additional part of this study in which we wanted to compare types of pheromone traps. We evaluated five very different trap designs: (1) a now standard wing trap (Pherocon 1C); (2) an omnidirectional trap patterned on those created by Sharma et al. (1973); (3) an omnidirectional trap modified with inserts that allowed adult males to enter the trap but not exit (welcome to the Hotel California); (4) a delta trap; and (5) a cone orifice trap originally described by Struble (1983) and manufactured in an early form by Hara Ltd. of Canada. We tested these traps in a series of commercial tomato or celery fields in Ventura, Motivating State Workers with Entomology