Role of the Fall Armyworm (Lepidoptera: Noctuidae) Pheromone and Other Factors in the Capture of Bumblebees (Hymenoptera: Aphidae) by Universal Moth Traps

Abstract

The International Pheromone Systems Universal moth trap (Unitrap), when baited with the pheromone of fall armyworm, Spodoptera frugiperda (J. E. Smith), has intermittently been observed to capture large numbers of bumblebees in addition to fall armyworm males. Studies were undertaken in Graham County, N.C., in 1988 and 1989 to determine the contributing factors. Investigation revealed that the yellow color of the traps was attractive to bumblebees, but the color alone did not influence their subsequent movement into the trap and resulting capture. Fall armyworm pheromone alone, particularly when used in combination with a No-Pest resin strip containing dichlorovos insecticide (to kill trapped insects), significantly increased the capture of bumblebees in yellow Unitraps. The green Unitrap alone was totally unattractive to bumblebees. Unitraps captured the greatest number of bumblebees when positioned adjacent to, and at the same height as, pollinating corn tassels. The number of captured bumblebees declined progressively as Unitrap height was lowered at 1-meter intervals from 4 to 1 m. Eleven species of bumblebees were identified from Unitrap captures. Abundant early spring rainfall in 1989 appeared to be primarily responsible for substantial reductions in the number of ground-nesting species of bumblebees during the summer.