Effect of Sex, Reproductive Maturity Stage and Trap Placement on Attraction of the Blueberry Maggot Fly (Diptera: Tephritidae) to Sphere and Pherocon AM Traps
We compared the performance of 9 cm diameter green spheres and red spheres and Pherocon AM traps, all baited with the same mixture of ammonium acetate and protein hydrolysate, in attracting blueberry maggot flies, Rhagoletis mendax Curran, of different reproductive maturity stages and sex. We also evaluated the effect of trap placement in relation to bush canopy (within the top 15 cm of the canopy, or near the base of the bush, 25 cm above ground, within a row) on attraction to these classes of flies. Results of this study showed that captures of flies on red or green spheres were better than on Pherocon AM traps, irrespective of maturity status or sex. Captures of flies were similar among traps placed in the top or the base of the bush, in the case of small bushes (1.2 m high). Traps placed within the top of the canopy captured more flies than those at the base, in the case of larger bushes (1.5-2.0 m high). At both positions, capture patterns were also not dependent on reproductive maturity or sex. Regression analysis between capture ratio of mature females on Pherocon AM/ Spheres and time revealed a significant inverse relationship, which might have been caused by differential aging of these traps. These data show that sphere traps capture more immature flies than Pherocon AM traps, and therefore can be deployed early in the season, when most flies present are immature females. The combination of more effective sphere traps and correct placement strategy depending on bush characteristics can further optimize blueberry maggot monitoring programs.