Three designs of pheromone-baited flight trap for the larger grain borer, Prostephanus truncatus (Horn) were compared in a daily-trapping trial in Ghana. Japanese-beetle (JB)-type traps, composed of a funnel surmounted by a cross-vane, captured two to three times more beetles than delta- and box-type sticky traps, which are currently the most commonly used designs. Japanese beetle traps have now been adopted by the Ghana National Trapping Network for P. truncatus. The higher efficiency of the JB traps has led to the discovery of the borer in two important maize-growing areas which had previously recorded zero catches using sticky delta-type traps. Analysis of correlation between replicates suggested that JB traps were the most consistent of the three trap designs (r = 0.88). The mode of entry of P. truncatus adults into different trap types, which may explain variations in catches from the different traps, is discussed.

The Integrated Pest Management (IPM) Programme under development at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) calls for a proper monitoring system. Experiments conducted in groundnut fields at ICRISAT Center near Hyderabad, in peninsular India, to establish the optimum height for pheromone traps to monitor Spodoptera lituta (F), indicated that the male flight pattern changes considerably during the cropping period. During the seedling stage (sowing to 6 weeks), most moths were caught at 0.5 and 1.0 m. In the initial growth phase (7–11 weeks), the traps at 4.0 m caught most moths. During the optimum growth phase (12th week to harvest) of the crop the traps at 1.0 m height trapped most moths. After harvest, the traps at 4.0 m again recorded the highest catch. These data are interpreted in terms of the migration pattern of S. litura moths during the crop season. We suggest monitoring this species, using 1 m height traps.

Males were found to be more active around 0300 hr, with a small peak after sunset (2000 hr). Irrespective of season, the peak flight activity of this species was around 0300 hr in groundnut fields.