| heal.abstract |
The efficacy of pheromone-baited multisurface traps and Lasiotraps (fig.) was compared with regards to mass-trapping male tobacco beetle (Lasioderma serricorne F.) in two insecticide-free tobacco stores (approximately 15 x 10 x 3 m) in Piraeus (southern Greece) for 15 months (Oct. 1990 through Dec. 1991). Continuous captures of L. serricorne on multisurface traps and Lasiotraps with and without addition of 10 mg anhydroserricornin (2,6-diethyl-3,5-dimethyl-3,4-dihydro-2H-pyran) revealed a total catch of 720 662 tobacco beetles on 2 pheromone-baited multisurface traps, 2 pheromone-baited Lasiotraps as well as 2 multisurface traps and 2 Lasiotraps without pheromone addition. The 2 pheromone-baited multisurface traps caught 501 481 tobacco beetles (approximately 69.6 %), while the 2 unbaited multisurface traps caught 131 865 L. serricirne (approximately 18.3 %). However, the 2 Lasiotraps with pheromone addition captured 59 265 tobacco beetles (approximately 8.2 %), whereas the 2 Lasiotraps without pheromone caught 28 051 tobacco beetles (approximately 3.9 %) only (table 2). It follows that pheromone-baited multisurface traps caught approximately 3.8 times more L. serricorne than multisurface traps lacking pheromone, while multisurface traps provided with pheromone captured approximately 8.5 times more tobacco beetles than pheromone-baited Lasiotraps. Moreover, pheromone-baited multisurface traps caught approximately 17.8 times more L. serricorne than pheromone-free Lasiotraps. It was concluded that multisurface traps (baited with 10 mg of anhydroserricornin) are very useful for mass-trapping of male L. serricorne and can promote insectistasis of this species in tobacco stores. Lasiotraps (baited with 10 mg of anhydroserricornin), having only one fifth the adhesive surface of multisurface traps, can detect infestations by tobacco beetles as early as multisurface traps and can thus be employed for monitoring populations of L. serricorne. The superiority of pheromone-baited multisurface traps over pheromone-baited Lasiotraps depends on the more efficient mass-trapping of male L. serricorne by the former, which is essentially due to their enlarged adhesive surface being vertically suspended around a concentric pheromone source. The elevated attractiveness of pheromone-baited multisurface traps is probably based on combined sensory stimulation of male tobacco beetles following simultaneous exposure to figural and pheromone stimuli acting in a synergistic optical-olfactory relationship. |
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