bottom/side guard combination. Five caps of each 

 treatment along with five unprotected caps were placed 

 atop spheres and offered to numerous and remarkably 

 aggressive wild gray squirrels. Assessments of physical 

 damage (as percentage of cap mass consumed) were 

 made daily for two weeks after deployment. 



Results 



As hypothesized for our first experiment, wax/ 

 sugar discs formulated with lower rates of paraffin 

 ( 1 0%- 1 5%, Table 1 ) released a greater amount of sugar 

 under rainfall than discs formulated with higher rates 

 of paraffm (20%-25%). Although superior at the outset, 

 discs formulated with the lowest rate of paraffin (10%) 

 only released an acceptable amount of sucrose (>5.0 

 grams per inch of rain) through four inches of 

 artificially applied rainfall. Conversely, caps 

 formulated with the greatest amount of paraftm (25%) 

 never provided an adequate release of sucrose. Caps 

 formulated with 15% 

 paraffin performed 

 somewhat better, 



offering an acceptable 

 release of sugar through 

 five inches of 

 accumulated rainfall, 

 and caps formulated 

 with 20% paraffin 

 released slightly less 

 sugar than those 

 formulated with 15% 

 paraffin through the first 

 six inches of rainfall. 

 However, sugar release 

 from caps of 20% 

 paraffin was by far the 

 most consistent through 

 simulated mid-season 

 treatments (four to eight 

 inches accumulated 

 rainfall). Therefore, we 

 elected to conduct 

 bioassays comparing 

 acceptability of spheres 

 equipped with caps 

 formulated with 15% 

 and 20% paraffin. 



In the first half of 



bioassays (two to four inches of rainfall), feeding 

 response of flies placed on spheres equipped with wax/ 

 sugar caps was excellent and equal between treatments 

 (Table 2). In fact, through four inches of rainfall, both 

 treatments yielded mean feeding times far greater than 

 needed to ensure adequate uptake of toxicant. Further, 

 both treatments stimulated 86% of exposed flies to feed 

 for more than 30 seconds, suggesting that both density 

 and coverage of sucrose on sphere surfaces remained 

 sufficient after four inches of rainfall. After six inches 

 of rainfall, however, neither treatment fared well. 

 Effectiveness of spheres fitted with 15% paraffin caps 

 retained only one-eighth of their feeding stimulant 

 power after six inches of rainfall, while spheres fitted 

 with 20% paraffin caps retained only one-half Along 

 with reduced duration of feeding, far fewer flies were 

 willing to feed on spheres at all, strongly indicating 

 that after six inches of rainfall, neither treatment could 

 be reliable as a control mechanism for AMF. 



In our second experiment, we compared the sugar 



Fruit Notes, Volume 66, 2001 



27 



