T3 

 Q) 



Q. 

 CD 

 O 



W 



O 



0) 



E 



c 



ro 

 .o 



10 20 30 40 



Amount of benzaldehyde released (mg/day) 



Figure 1. Relationship between total PC captures by Circle traps and amount of 

 benzaldehyde released from 15-ml white polyethylene vials positioned ~4 inches above 

 trap tops. Amounts of benzaldehyde released were 0, 10, 20, and 40 mg/day, each in 

 association with PC pheromone (1 mg of grandisoic acid per day). 



period, traps baited with the 'IPM Technologies' 

 formulation did not capture any PCs. However, 17-24 

 days after the initial baiting, the 'IPM Technologies' 

 and the 'Great Lakes IPM' formulations performed 

 better than the white vial and the clear vials but, 

 nevertheless, did not perform better than unbailed traps. 

 From 25-32 days, all traps captured similar numbers 

 of PCs except traps baited with the 'IPM Technologies' 

 formulation, which captured no PCs. Overall, the 

 formulations '4 clear vials', '1 white vial', and the 

 'Great Lakes IPM' were about equally attractive to PCs, 

 whereas the 'EPM Technologies' formulation was the 

 least attractive. 



In the fourth experiment, wherein all dispensers 

 of benzaldehyde were placed 4 inches above Circle 

 trap tops, results show a strong linear relationship 

 between the amount of benzaldehyde released (in 

 association with PC pheromone) and the total number 

 of PCs captured by Circle traps (Fig. 1 ). This suggests 

 that, at least for Circle traps, the response of PCs to 

 benzaldehyde in association with PC pheromone 

 increases as the amount of benzaldehyde increases (up 

 to the maximum release rate tested of about 40 mg per 

 day). 



Conclusions 



Four conclusions can be drawTi from this series of 

 experiments. 



First, white polyethylene vials releasing 

 benzaldehyde performed as well as either the clear vials 

 used in the 2000 field test or the other formulations of 

 benzaldehyde evaluated (Great Lakes IPM and IPM 

 Technologies). Therefore, white polyethylene vials 

 (particularly the UV-light-protected 15-ml vials [see 

 below]) can be used as devices to dispense 

 benzaldehyde effectively in future tests. 



Second, results from the first and second 

 experiments suggest, for the most part, that when 

 dispensers are placed inside of cylinder trap tops, the 

 odor of benzaldehyde may become repellent at close 

 range, thus reducing the ability of cylinder traps to 

 capture PCs. This was particularly true for both the 

 'Great Lakes IPM' and 'IPM Technologies' 

 formulations but not for the ' 1 -white-vial' or '4-clear- 

 vials' formulations (in experiment 1), and the '5 -white- 

 vials' treatment (in experiment 2). Consequently, we 

 believe that benzaldehyde-releasing dispensers should 

 be placed outside of trap tops to avoid close-range 



Fruit Notes, Volume 67, Fall, 2002 



