Evaluation of pheromone lures, trap designs and placement heights for monitoring the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) in maize fields of Kenya

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), is a damaging crop pest that has recently invaded and established across Africa from its native tropical and subtropical regions of the Americas. To develop an improved monitoring system for the FAW, we evaluated five commercial sex pheromone lures (Shenzhen Bio-global, FALLTRACK, Enlure, P061-Lure and PH-869-1PR), three trap types (delta, bucket, and water-pan) and six placement heights (ground level, 0.5, 1, 1.5, 2 m above the ground and 0.2 m above the crop canopy) in replicated field trials at representative maize growing agroecologies of Kenya. Water-pan traps baited with the lures PH-869-1PR and P061-Lure captured the highest number of moths, whereas delta traps captured the least number of moths regardless of the pheromone lure used. Water-pan traps baited with Enlure and FALLTRACK lures captured more non-target insects than traps baited with the other lures. Traps placed at 1.5 m and 2 m above the ground captured more FAW moths than traps at the other placement heights. Genetic studies revealed no discernible differences between lures in the proportions of FAW strains captured. We recommend PH-869-1PR baited water-pan and bucket traps at a placement height of 1.5 m above ground for monitoring the FAW in Kenya. Moreover, we discussed the merits and drawbacks of different pheromone lure and trap combinations, and placement heights.