Testing the Efficacy of Aromatherapy at the World’s Largest Eclosion Facility for Sterile Males of the Mediterranean Fruit Fly (Diptera: Tephritidae)

Exposure to the aroma of ginger root oil (GRO) increases the mating competitiveness of adult sterile males of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann). This effect has been observed under various exposure regimes, ranging from small groups of males (25 individuals) held in small cups to large numbers of males (14 million individuals) held in trailers. Here, we assess the efficacy of GRO treatment at an even larger scale at the world’s largest eclosion facility for sterile male medflies located in Retalhuleu, Guatemala. GRO exposure was conducted in several different holding rooms each with a particular dose (0.37–0.91 ml GRO per m3 room volume) and each with a unique number of sterile males (59–127 million adult males per room). Treated sterile males were exposed to GRO at 3 d of age for 24 h and then held 24 h before testing. Control sterile males were tested at the same age as treated males but were held in rooms not receiving GRO application. In field tents, we released 50 sterile males (treated or control), 50 wild males, and 50 wild females and collected copulating pairs. Over all trials, control sterile males obtained 19%–26% of the total matings per replicate, whereas treated sterile males obtained significantly higher proportions of the total matings (34%–41%) for all doses tested. Among treated sterile males, relative mating success did not vary significantly with GRO dose. These findings suggest that the use of GRO aromatherapy in the large holding rooms in the Retalhuleu facility will substantially enhance the mating competitiveness of the sterile male medflies